diff --git a/xml/System.Globalization/CompareInfo.xml b/xml/System.Globalization/CompareInfo.xml
index 61aa16bc114..9ad3ca363e5 100644
--- a/xml/System.Globalization/CompareInfo.xml
+++ b/xml/System.Globalization/CompareInfo.xml
@@ -2222,13 +2222,23 @@ Use <xref:System.Globalization.CompareInfo.GetSortKeyLength(System.ReadOnlySpan{
         <Parameter Name="matchLength" Type="System.Int32" RefType="out" Index="3" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <param name="value">To be added.</param>
-        <param name="options">To be added.</param>
-        <param name="matchLength">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="source">The read-only span of characters to search within.</param>
+        <param name="value">The read-only span of characters containing the substring to locate within <paramref name="source" />.</param>
+        <param name="options">The <see cref="T:System.Globalization.CompareOptions" /> to use during the search.</param>
+        <param name="matchLength">When this method returns, contains the number of characters of <paramref name="source" /> that matched the desired value. This may be different than the length of <paramref name="value" /> if a linguistic comparison is performed. Set to 0 if <paramref name="value" /> is not found within <paramref name="source" />.</param>
+        <summary>Searches for the first occurrence of a substring within a source string.</summary>
+        <returns>The zero-based index into <paramref name="source" /> where the substring <paramref name="value" /> first appears; or a negative value if <paramref name="value" /> cannot be found within <paramref name="source" />.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+This method has greater overhead than other <xref:System.Globalization.CompareInfo.IndexOf%2A> overloads which don't take a `matchLength` argument. Call this overload only if you require the match length information.
+
+          ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="options" /> contains an unsupported combination of flags.</exception>
       </Docs>
     </Member>
     <Member MemberName="IndexOf">
@@ -3097,13 +3107,24 @@ Use <xref:System.Globalization.CompareInfo.GetSortKeyLength(System.ReadOnlySpan{
         <Parameter Name="matchLength" Type="System.Int32" RefType="out" Index="3" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <param name="prefix">To be added.</param>
-        <param name="options">To be added.</param>
-        <param name="matchLength">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="source">The read-only span of characters to search within.</param>
+        <param name="prefix">The read-only span of characters containing the prefix to attempt to match at the start of <paramref name="source" />.</param>
+        <param name="options">The <see cref="T:System.Globalization.CompareOptions" /> to use during the match.</param>
+        <param name="matchLength">When this method returns, contains the number of characters of <paramref name="source" /> that matched the desired prefix. This may be different than the length of <paramref name="prefix" /> if a linguistic comparison is performed. Set to 0 if the prefix did not match.</param>
+        <summary>Determines whether a string starts with a specific prefix.</summary>
+        <returns>
+          <see langword="true" /> if <paramref name="prefix" /> occurs at the start of <paramref name="source" />; otherwise, <see langword="false" />.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+This method has greater overhead than other <xref:System.Globalization.CompareInfo.IsPrefix(System.String,System.String,System.Globalization.CompareOptions)> overloads which don't take a `matchLength` argument. Call this overload only if you require the match length information.
+
+          ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="options" /> contains an unsupported combination of flags.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="IsSortable">
@@ -3556,13 +3577,24 @@ Use <xref:System.Globalization.CompareInfo.GetSortKeyLength(System.ReadOnlySpan{
         <Parameter Name="matchLength" Type="System.Int32" RefType="out" Index="3" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <param name="suffix">To be added.</param>
-        <param name="options">To be added.</param>
-        <param name="matchLength">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="source">The read-only span of characters to search within.</param>
+        <param name="suffix">The read-only span of characters containing the suffix to attempt to match at the end of <paramref name="source" />.</param>
+        <param name="options">The <see cref="T:System.Globalization.CompareOptions" /> to use during the match.</param>
+        <param name="matchLength">When this method returns, contains the number of characters of <paramref name="source" /> that matched the desired suffix. This may be different than the length of <paramref name="suffix" /> if a linguistic comparison is performed. Set to 0 if the suffix did not match.</param>
+        <summary>Determines whether a string ends with a specific suffix.</summary>
+        <returns>
+          <see langword="true" /> if <paramref name="suffix" /> occurs at the end of <paramref name="source" />; otherwise, <see langword="false" />.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+This method has greater overhead than other <xref:System.Globalization.CompareInfo.IsSuffix(System.String,System.String,System.Globalization.CompareOptions)> overloads which don't take a `matchLength` argument. Call this overload only if you require the match length information.
+
+          ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="options" /> contains an unsupported combination of flags.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="LastIndexOf">
@@ -4218,13 +4250,23 @@ Use <xref:System.Globalization.CompareInfo.GetSortKeyLength(System.ReadOnlySpan{
         <Parameter Name="matchLength" Type="System.Int32" RefType="out" Index="3" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="source">To be added.</param>
-        <param name="value">To be added.</param>
-        <param name="options">To be added.</param>
-        <param name="matchLength">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="source">The read-only span of characters to search within.</param>
+        <param name="value">The read-only span of characters containing the substring to locate within <paramref name="source" />.</param>
+        <param name="options">The <see cref="T:System.Globalization.CompareOptions" /> to use during the search.</param>
+        <param name="matchLength">When this method returns, contains the number of characters of <paramref name="source" /> that matched the desired value. This may be different than the length of <paramref name="value" /> if a linguistic comparison is performed. Set to 0 if <paramref name="value" /> is not found within <paramref name="source" />.</param>
+        <summary>Searches for the last occurrence of a substring within a source string.</summary>
+        <returns>The zero-based index into <paramref name="source" /> where the substring <paramref name="value" /> last appears; or a negative number if <paramref name="value" /> cannot be found within <paramref name="source" />.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+This method has greater overhead than other <xref:System.Globalization.CompareInfo.LastIndexOf%2A> overloads which don't take a `matchLength` argument. Call this overload only if you require the match length information.
+
+          ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentException">
+          <paramref name="options" /> contains an unsupported combination of flags.</exception>
       </Docs>
     </Member>
     <Member MemberName="LastIndexOf">