Office 365 (Outlook iOS and Android) - Focused Inbox
What is Focused Inbox? - This article provides information on how Focused Inbox works, and a brief section on how to turn focused inbox on and off.
Optimize the Outlook mobile app for your iOS or Android phone - This article provides instructions for optimizing the Outlook mobile app, including how to turn Focused Inbox On/Off.
Outlook for iOS and Android Help - This article provides various resources for Outlook users with iOS and Android devices.