This article lists necessary steps to restore email service using the builtin mail app on iPhone/iPad
The iOS mail app does not require any setting changes after your email account has been migrated to Microsoft Servers.
If mail does not receive any new emails it is recommended to restart the iPhone/iPad by powering the device on and off.
Also ensure the device is connected to and has a working internet connection. You can test this by opening a web browser and attempting to open a website.