diff --git a/xml/System.IO/File.xml b/xml/System.IO/File.xml
index ca18a64fcd9..1f89926ed5c 100644
--- a/xml/System.IO/File.xml
+++ b/xml/System.IO/File.xml
@@ -150,10 +150,40 @@
         <Parameter Name="bytes" Type="System.Byte[]" Index="1" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="bytes">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="path">The file to append to.</param>
+        <param name="bytes">The bytes to append to the file.</param>
+        <summary>
+          <para>Appends the specified byte array to the end of the file at the given path.</para>
+          <para>If the file doesn't exist, this method creates a new file.</para>
+        </summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> or <paramref name="bytes" /> is <see langword="null" />.
+        </exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.IO.PathTooLongException">The specified path, file name, or both exceed the system-defined maximum length.</exception>
+        <exception cref="T:System.IO.DirectoryNotFoundException">The specified path is invalid (for example, it is on an unmapped drive).</exception>
+        <exception cref="T:System.IO.IOException">An I/O error occurred while opening the file.</exception>
+        <exception cref="T:System.UnauthorizedAccessException">
+          <para>
+            <paramref name="path" /> specified a file that is read-only.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a file that is hidden.
+          </para>
+            <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a directory.
+          </para>
+          <para>-or-</para>
+          <para>The caller does not have the required permission.</para>
+          <para>-or-</para>
+          <para>This operation is not supported on the current platform.</para>
+        </exception>
+        <exception cref="T:System.NotSupportedException">
+          <paramref name="path" /> is in an invalid format.</exception>
       </Docs>
     </Member>
     <Member MemberName="AppendAllBytes">
@@ -195,10 +225,38 @@
         <Parameter Name="bytes" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="1" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="bytes">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="path">The file to append to.</param>
+        <param name="bytes">The bytes to append to the file.</param>
+        <summary>
+          <para>Appends the specified byte array to the end of the file at the given path.</para>
+          <para>If the file doesn't exist, this method creates a new file.</para>
+        </summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.IO.PathTooLongException">The specified path, file name, or both exceed the system-defined maximum length.</exception>
+        <exception cref="T:System.IO.DirectoryNotFoundException">The specified path is invalid (for example, it is on an unmapped drive).</exception>
+        <exception cref="T:System.IO.IOException">An I/O error occurred while opening the file.</exception>
+        <exception cref="T:System.UnauthorizedAccessException">
+          <para>
+            <paramref name="path" /> specified a file that is read-only.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a file that is hidden.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a directory.
+          </para>
+          <para>The caller does not have the required permission.</para>
+          <para>-or-</para>
+          <para>This operation is not supported on the current platform.</para>
+        </exception>
+        <exception cref="T:System.NotSupportedException">
+          <paramref name="path" /> is in an invalid format.</exception>
       </Docs>
     </Member>
     <Member MemberName="AppendAllBytesAsync">
@@ -230,12 +288,21 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="bytes">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="path">The file to append to.</param>
+        <param name="bytes">The bytes to append to the file.</param>
+        <param name="cancellationToken">The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" />.</param>
+        <summary>
+          <para>Asynchronously appends the specified byte array to the end of the file at the given path.</para>
+          <para>If the file doesn't exist, this method creates a new file. If the operation is canceled, the task will return in a canceled state.</para>
+        </summary>
         <returns>To be added.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> or <paramref name="bytes" /> is <see langword="null" />.
+        </exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.OperationCanceledException">The cancellation token was canceled. This exception is stored into the returned task.</exception>
       </Docs>
     </Member>
     <Member MemberName="AppendAllBytesAsync">
@@ -271,12 +338,20 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="bytes">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="path">The file to append to.</param>
+        <param name="bytes">The bytes to append to the file.</param>
+        <param name="cancellationToken">The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" />.</param>
+        <summary>
+          <para>Asynchronously appends the specified byte array to the end of the file at the given path.</para>
+          <para>If the file doesn't exist, this method creates a new file. If the operation is canceled, the task will return in a canceled state.</para>
+        </summary>
         <returns>To be added.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.OperationCanceledException">The cancellation token was canceled. This exception is stored into the returned task.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="AppendAllLines">
@@ -619,10 +694,40 @@
         <Parameter Name="contents" Type="System.ReadOnlySpan&lt;System.Char&gt;" Index="1" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="contents">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="path">The file to append to.</param>
+        <param name="contents">The characters to write to the file.</param>
+        <summary>Appends the specified string to the file, creating the file if it does not already exist.</summary>
+        <remarks>
+          <para>Given a string and a file path, this method opens the specified file, appends the string to the end of the file using the specified encoding,</para>
+          <para>and then closes the file. The file handle is guaranteed to be closed by this method, even if exceptions are raised. The method creates the file</para>
+          <para>if it doesn't exist, but it doesn't create new directories. Therefore, the value of the path parameter must contain existing directories.</para>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.IO.PathTooLongException">The specified path, file name, or both exceed the system-defined maximum length.</exception>
+        <exception cref="T:System.IO.DirectoryNotFoundException">The specified path is invalid (for example, it is on an unmapped drive).</exception>
+        <exception cref="T:System.IO.IOException">An I/O error occurred while opening the file.</exception>
+        <exception cref="T:System.UnauthorizedAccessException">
+          <para>
+            <paramref name="path" /> specified a file that is read-only.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a file that is hidden.
+          </para>
+            <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a directory.
+          </para>
+          <para>-or-</para>
+          <para>The caller does not have the required permission.</para>
+          <para>-or-</para>
+          <para>This operation is not supported on the current platform.</para>
+        </exception>
+        <exception cref="T:System.NotSupportedException">
+          <paramref name="path" /> is in an invalid format.</exception>
       </Docs>
     </Member>
     <Member MemberName="AppendAllText">
@@ -763,11 +868,42 @@
         <Parameter Name="encoding" Type="System.Text.Encoding" Index="2" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="contents">To be added.</param>
-        <param name="encoding">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="path">The file to append to.</param>
+        <param name="contents">The characters to write to the file.</param>
+        <param name="encoding">The encoding to apply to the string.</param>
+        <summary>Appends the specified string to the file, creating the file if it does not already exist.</summary>
+        <remarks>
+          <para>Given a string and a file path, this method opens the specified file, appends the string to the end of the file using the specified encoding,</para>
+          <para>and then closes the file. The file handle is guaranteed to be closed by this method, even if exceptions are raised. The method creates the file</para>
+          <para>if it doesn't exist, but it doesn't create new directories. Therefore, the value of the path parameter must contain existing directories.</para>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> or <paramref name="encoding" /> is <see langword="null" />.
+        </exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.IO.PathTooLongException">The specified path, file name, or both exceed the system-defined maximum length.</exception>
+        <exception cref="T:System.IO.DirectoryNotFoundException">The specified path is invalid (for example, it is on an unmapped drive).</exception>
+        <exception cref="T:System.IO.IOException">An I/O error occurred while opening the file.</exception>
+        <exception cref="T:System.UnauthorizedAccessException">
+          <para>
+            <paramref name="path" /> specified a file that is read-only.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a file that is hidden.
+          </para>
+            <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a directory.
+          </para>
+          <para>-or-</para>
+          <para>The caller does not have the required permission.</para>
+          <para>-or-</para>
+          <para>This operation is not supported on the current platform.</para>
+        </exception>
+        <exception cref="T:System.NotSupportedException">
+          <paramref name="path" /> is in an invalid format.</exception>
       </Docs>
     </Member>
     <Member MemberName="AppendAllText">
@@ -909,12 +1045,13 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="contents">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="path">The file to append the specified string to.</param>
+        <param name="contents">The characters to append to the file.</param>
+        <param name="cancellationToken">The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" />.</param>
+        <summary>Asynchronously opens a file or creates a file if it does not already exist, appends the specified string to the file, and then closes the file.</summary>
+        <returns>A task that represents the asynchronous append operation.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.OperationCanceledException">The cancellation token was canceled. This exception is stored into the returned task.</exception>
       </Docs>
     </Member>
     <Member MemberName="AppendAllTextAsync">
@@ -1005,13 +1142,14 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="3" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="contents">To be added.</param>
-        <param name="encoding">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="path">The file to append the specified string to.</param>
+        <param name="contents">The characters to append to the file.</param>
+        <param name="encoding">The character encoding to use.</param>
+        <param name="cancellationToken">The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" />.</param>
+        <summary>Asynchronously opens a file or creates the file if it does not already exist, appends the specified string to the file using the specified encoding, and then closes the file.</summary>
+        <returns>A task that represents the asynchronous append operation.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.OperationCanceledException">The cancellation token was canceled. This exception is stored into the returned task.</exception>
       </Docs>
     </Member>
     <Member MemberName="AppendAllTextAsync">
@@ -6908,10 +7046,36 @@ It is not possible to change the compression status of a <xref:System.IO.File> o
         <Parameter Name="bytes" Type="System.ReadOnlySpan&lt;System.Byte&gt;" Index="1" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="bytes">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="path">The file to write to.</param>
+        <param name="bytes">The bytes to write to the file.</param>
+        <summary>Creates a new file, writes the specified byte array to the file, and then closes the file. If the target file already exists, it is truncated and overwritten.</summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.IO.PathTooLongException">The specified path, file name, or both exceed the system-defined maximum length.</exception>
+        <exception cref="T:System.IO.DirectoryNotFoundException">The specified path is invalid (for example, it is on an unmapped drive).</exception>
+        <exception cref="T:System.IO.IOException">An I/O error occurred while opening the file.</exception>
+        <exception cref="T:System.UnauthorizedAccessException">
+          <para>
+            <paramref name="path" /> specified a file that is read-only.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a file that is hidden.
+          </para>
+            <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a directory.
+          </para>
+          <para>-or-</para>
+          <para>The caller does not have the required permission.</para>
+          <para>-or-</para>
+          <para>This operation is not supported on the current platform.</para>
+        </exception>
+        <exception cref="T:System.NotSupportedException">
+          <paramref name="path" /> is in an invalid format.</exception>
       </Docs>
     </Member>
     <Member MemberName="WriteAllBytesAsync">
@@ -6993,12 +7157,17 @@ It is not possible to change the compression status of a <xref:System.IO.File> o
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="bytes">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="path">The file to write to.</param>
+        <param name="bytes">The bytes to write to the file.</param>
+        <param name="cancellationToken">The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" />.</param>
+        <summary>Asynchronously creates a new file, writes the specified byte array to the file, and then closes the file. If the target file already exists, it is truncated and overwritten.</summary>
+        <returns>A task that represents the asynchronous write operation.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.OperationCanceledException">The cancellation token was canceled. This exception is stored into the returned task.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="WriteAllLines">
@@ -7551,10 +7720,38 @@ It is not possible to change the compression status of a <xref:System.IO.File> o
         <Parameter Name="contents" Type="System.ReadOnlySpan&lt;System.Char&gt;" Index="1" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="contents">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="path">The file to write to.</param>
+        <param name="contents">The characters to write to the file.</param>
+        <summary>
+          <para>Creates a new file, writes the specified string to the file, and then closes the file.</para>
+          <para>If the target file already exists, it is truncated and overwritten.</para>
+        </summary>
+        <remarks>This method uses UTF-8 encoding without a Byte-Order Mark (BOM), so using the <see cref="M:System.Text.Encoding.GetPreamble" /> method will return an empty byte array. If it is necessary to include a UTF-8 identifier, such as a byte order mark, at the beginning of a file, use the <see cref="M:System.IO.File.WriteAllText(System.String,System.ReadOnlySpan{System.Char},System.Text.Encoding)" /> method.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.IO.PathTooLongException">The specified path, file name, or both exceed the system-defined maximum length.</exception>
+        <exception cref="T:System.IO.DirectoryNotFoundException">The specified path is invalid (for example, it is on an unmapped drive).</exception>
+        <exception cref="T:System.IO.IOException">An I/O error occurred while opening the file.</exception>
+        <exception cref="T:System.UnauthorizedAccessException">
+          <para>
+            <paramref name="path" /> specified a file that is read-only.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a file that is hidden.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a directory.
+          </para>
+          <para>-or-</para>
+          <para>This operation is not supported on the current platform.</para>
+          <para>The caller does not have the required permission.</para>
+        </exception>
+        <exception cref="T:System.NotSupportedException">
+          <paramref name="path" /> is in an invalid format.</exception>
       </Docs>
     </Member>
     <Member MemberName="WriteAllText">
@@ -7699,11 +7896,41 @@ It is not possible to change the compression status of a <xref:System.IO.File> o
         <Parameter Name="encoding" Type="System.Text.Encoding" Index="2" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="contents">To be added.</param>
-        <param name="encoding">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="path">The file to write to.</param>
+        <param name="contents">The characters to write to the file.</param>
+        <param name="encoding">The encoding to apply to the string.</param>
+        <summary>
+          <para>Creates a new file, writes the specified string to the file using the specified encoding, and then closes the file.</para>
+          <para>If the target file already exists, it is truncated and overwritten.</para>
+        </summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="path" /> or <paramref name="encoding" /> is <see langword="null" />.
+        </exception>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="path" /> is empty.</exception>
+        <exception cref="T:System.IO.PathTooLongException">The specified path, file name, or both exceed the system-defined maximum length.</exception>
+        <exception cref="T:System.IO.DirectoryNotFoundException">The specified path is invalid (for example, it is on an unmapped drive).</exception>
+        <exception cref="T:System.IO.IOException">An I/O error occurred while opening the file.</exception>
+        <exception cref="T:System.UnauthorizedAccessException">
+          <para>
+            <paramref name="path" /> specified a file that is read-only.
+          </para>
+          <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a file that is hidden.
+          </para>
+            <para>-or-</para>
+          <para>
+            <paramref name="path" /> specified a directory.
+          </para>
+          <para>-or-</para>
+          <para>The caller does not have the required permission.</para>
+          <para>-or-</para>
+          <para>This operation is not supported on the current platform.</para>
+        </exception>
+        <exception cref="T:System.NotSupportedException">
+          <paramref name="path" /> is in an invalid format.</exception>
       </Docs>
     </Member>
     <Member MemberName="WriteAllText">
@@ -7847,12 +8074,16 @@ It is not possible to change the compression status of a <xref:System.IO.File> o
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="contents">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="path">The file to write to.</param>
+        <param name="contents">The characters to write to the file.</param>
+        <param name="cancellationToken">The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" />.</param>
+        <summary>
+          <para>Asynchronously creates a new file, writes the specified string to the file, and then closes the file.</para>
+          <para>If the target file already exists, it is truncated and overwritten.</para>
+        </summary>
+        <returns>A task that represents the asynchronous write operation.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.OperationCanceledException">The cancellation token was canceled. This exception is stored into the returned task.</exception>
       </Docs>
     </Member>
     <Member MemberName="WriteAllTextAsync">
@@ -7943,13 +8174,17 @@ It is not possible to change the compression status of a <xref:System.IO.File> o
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="3" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="path">To be added.</param>
-        <param name="contents">To be added.</param>
-        <param name="encoding">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="path">The file to write to.</param>
+        <param name="contents">The characters to write to the file.</param>
+        <param name="encoding">The encoding to apply to the string.</param>
+        <param name="cancellationToken">The token to monitor for cancellation requests. The default value is <see cref="P:System.Threading.CancellationToken.None" />.</param>
+        <summary>
+          <para>Asynchronously creates a new file, writes the specified string to the file using the specified encoding, and then closes the file.</para>
+          <para>If the target file already exists, it is truncated and overwritten.</para>
+        </summary>
+        <returns>A task that represents the asynchronous write operation.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.OperationCanceledException">The cancellation token was canceled. This exception is stored into the returned task.</exception>
       </Docs>
     </Member>
     <Member MemberName="WriteAllTextAsync">
diff --git a/xml/System.IO/Path.xml b/xml/System.IO/Path.xml
index d362edd8a3a..573ad4d7da5 100644
--- a/xml/System.IO/Path.xml
+++ b/xml/System.IO/Path.xml
@@ -355,9 +355,9 @@ This method is intended to concatenate individual strings into a single string t
         </Parameter>
       </Parameters>
       <Docs>
-        <param name="paths">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="paths">A span of parts of the path.</param>
+        <summary>Combines a span of strings into a path.</summary>
+        <returns>The combined paths.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -2890,9 +2890,9 @@ Note that rooted paths can be either absolute (that is, fully qualified) or rela
         </Parameter>
       </Parameters>
       <Docs>
-        <param name="paths">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="paths">A span of paths.</param>
+        <summary>Concatenates a span of paths into a single path.</summary>
+        <returns>The concatenated path.</returns>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.IO/StreamWriter.xml b/xml/System.IO/StreamWriter.xml
index a18ac46a6e7..6e5e92b77d7 100644
--- a/xml/System.IO/StreamWriter.xml
+++ b/xml/System.IO/StreamWriter.xml
@@ -2117,9 +2117,9 @@ See <xref:System.IO.TextWriter.Write(System.String,System.Object[])> for a descr
         </Parameter>
       </Parameters>
       <Docs>
-        <param name="format">To be added.</param>
-        <param name="arg">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="format">A composite format string.</param>
+        <param name="arg">An object span that contains zero or more objects to format and write.</param>
+        <summary>Writes a formatted string to the stream, using the same semantics as <see cref="M:System.String.Format(System.String,System.ReadOnlySpan{System.Object})" />.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -2976,9 +2976,9 @@ See <xref:System.IO.TextWriter.WriteLine(System.String,System.Object[])> for a d
         </Parameter>
       </Parameters>
       <Docs>
-        <param name="format">To be added.</param>
-        <param name="arg">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="format">A composite format string.</param>
+        <param name="arg">An object span that contains zero or more objects to format and write.</param>
+        <summary>Writes out a formatted string and a new line to the stream, using the same semantics as <see cref="M:System.String.Format(System.String,System.ReadOnlySpan{System.Object})" />.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
diff --git a/xml/System.IO/TextWriter.xml b/xml/System.IO/TextWriter.xml
index e8c5c42b973..f1a05c07869 100644
--- a/xml/System.IO/TextWriter.xml
+++ b/xml/System.IO/TextWriter.xml
@@ -439,10 +439,15 @@
         </Parameter>
       </Parameters>
       <Docs>
-        <param name="writers">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="writers">The <see cref="T:System.IO.TextWriter" /> instances to which all operations should be broadcast (multiplexed).</param>
+        <summary>Creates an instance of <see cref="T:System.IO.TextWriter" /> that writes supplied inputs to each of the writers in <paramref name="writers" />.</summary>
+        <returns>An instance of <see cref="T:System.IO.TextWriter" /> that writes supplied inputs to each of the writers in <paramref name="writers" /></returns>
+        <remarks>
+          <para>The resulting instance will delegate each operation to each of the writers in <paramref name="writers" />. For example, calling <see cref="M:System.IO.TextWriter.Write(System.Char)" /> will write the specified char to each writer, one after the other. The writers will be written to in the same order as they are specified in <paramref name="writers" />. An exception from the operation on one writer will prevent the operation from being performed on subsequent writers.</para>
+          <para><see cref="P:System.IO.TextWriter.Encoding" /> and <see cref="P:System.IO.TextWriter.FormatProvider" /> will return the corresponding object from first writer in <paramref name="writers" />.</para>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">
+          <paramref name="writers" /> is <see langword="null" /> or it contains a <see langword="null" />.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="Dispose">
@@ -2470,9 +2475,9 @@ This method is equivalent to `Write(stringBuilder.ToString())`, but it uses the
         </Parameter>
       </Parameters>
       <Docs>
-        <param name="format">To be added.</param>
-        <param name="arg">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="format">A composite format string.</param>
+        <param name="arg">An object span that contains zero or more objects to format and write.</param>
+        <summary>Writes a formatted string to the text stream, using the same semantics as <see cref="M:System.String.Format(System.String,System.ReadOnlySpan{System.Object})" />.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -4627,9 +4632,9 @@ For a list of common I/O tasks, see [Common I/O Tasks](/dotnet/standard/io/commo
         </Parameter>
       </Parameters>
       <Docs>
-        <param name="format">To be added.</param>
-        <param name="arg">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="format">A composite format string.</param>
+        <param name="arg">An object span that contains zero or more objects to format and write.</param>
+        <summary>Writes out a formatted string and a new line to the text stream, using the same semantics as <see cref="M:System.String.Format(System.String,System.ReadOnlySpan{System.Object})" />.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>