User Configuration > Administrative Templates > Microsoft Office 2016 > Miscellaneous
User
HKCU\software\policies\microsoft\office\16.0\common\sharepointintegration
This policy setting changes the destination URL of the Learn more about SharePoint hyperlink located on the Save to SharePoint form in the Backstage view for Word, PowerPoint, Excel, Visio, and Project. If you enable this policy setting, the hyperlink destination you provide will be used. If you disable or do not configure this policy setting, then the default destination URL to Learn more about SharePoint will be used.