At the School and Group levels, you can bulk wipe devices under Settings > General. Click the Wipe Devices button to wipe all devices.
There is also an option for wiping specific devices by .csv file under Settings > CSV Import at the organization level.
Note: In order to wipe macOS/OS X devices, a 6-digit pin must be either entered into the box for the school or group wiping, or in the second column of the .csv file containing the Mac’s serial number.
Note: Bulk wiping devices will remove device supervision and MDM payloads.