NOTE - several folks asked for the information that was in this blog when the app was in preview (for context). Prior to the app being publicly available, you added the following custom app bundle ID's and apps.
1 - For Android App Protection Policies, add the Office Hub, Office Hub [HL], and Office Hub [ROW] apps.
2 - For iOS App Protection Policies, use com.microsoft.officemobile as a custom app bundle ID.
2/20/20: Updated with availability of the iOS and Android app
3/6/2020: Updated with the prior information that was in the blog for context.
3/25/2020: Updated with how to block URLs or IP addresses.