Apple allows iOS14 users to select a different email app to be the default. The switch to Outlook is easy, and you can also pin Outlook to the Home Screen to make it easier to access the app. Remember to check for users running iOS12 because Microsoft no longer supports these devices are for Outlook updates. Fortunately, PowerShell helps to find devices running iOS12 by checking their mobile device connection status.
https://office365itpros.com/2020/09/21/making-outlook-default-mail-app-ios14/
