How AirWatch MDM works?
Android has a concept called "device administrators" to allow for this kind of control. A device administrator is a special app given extra permissions that normal apps don't have, such as controlling what other apps are allowed to be installed, enforcing security policies, and remote-wiping the device.

You can learn more about how this works under-the-hood on the Android Developers website.

This feature is built into the Android permission model, so it doesn't need the phone to be rooted.