Note: if the device has Supervised Mode enabled and you would like to disable it, you will need to erase the device even after removing it from MDM. This will send a command to the device instructing it to delete the MDM profile. If the device was enrolled manually or using Apple Configurator: there are two ways that devices can be unenrolled. To fully remove a device from all forms of management, the necessary process will ultimately depend on how the device became enrolled in MDM.
However, there are ways to enroll devices that restrict this capability, as discussed in this article. By default, Apple allows the MDM profile to be removed from devices via Settings at any time.
