Forum Discussion
Where do the contacts come from that are at choice for a people picker column in sharepoint online?
A customer was asking this question because a few people in his company were surprised finding private contacts within their SharePoint Online when starting to type a people's name in a people picker...
Since all the users for M365 are stored on Azure AD, SharePoint Online and other services utilize the AD for Users, Groups and Contacts.
You can find more info here - https://docs.microsoft.com/en-us/azure/active-directory/hybrid/concept-azure-ad-connect-sync-user-and-contacts