MDM stands for Mobile Device Management. When a business or educational institution purchases a batch of devices from Apple, they will often enroll them in a program which allows the organization to add restrictions to all their devices and essentially have authority over them all.
With MDM active on your device, you won’t be able to activate it without permission from the supervising authority. Therefore, checking the MDM status has become just as essential as checking the Find My iPhone status.
IMEI Number: ###############
Serial Number: ************
MDM Enrollment Status: ON
IMEI Number: ###############
Serial Number: ************
MDM Enrollment Status: OFF