The Users With Mobile Devices report displays a list of each user who have accessed their Office 365 mailbox through a mobile device using ActiveSync.
The Data Table
The table lists each user and more information about their device. You can add, remove or re-order these columns to display the information in a customised way.
This report can be filtered, allowing you to generate bespoke reports about the devices in a particular Department, Country or any other category you choose.
As with all of the reports, this information can be customized, filtered and scheduled.