edit for sharepoint requirements

Author: diberry

articles/cognitive-services/QnAMaker/How-To/add-sharepoint-datasources.md

@@ -15,7 +15,8 @@ If the QnA Maker knowledge base manager is not the Active Directory manager, you
 
 ## Prerequisites
 
-QnA Maker uses Microsoft Graph for permissions. If your SharePoint is on-premises, you won't be able to extract from SharePoint because Microsoft Graph won't be able to determine permissions.
+* Cloud-based SharePoint - QnA Maker uses Microsoft Graph for permissions. If your SharePoint is on-premises, you won't be able to extract from SharePoint because Microsoft Graph won't be able to determine permissions.
+* URL format - QnA Maker only supports SharePoint urls which are generated for sharing and are of format https://*.sharepoint.com
 
 ## Add supported file types to knowledge base