As the name suggests, geofencing creates a virtual fence(known as a geofence) based on a geo-location range and ensures certain actions are performed automatically on the device, when it leaves the specified range. Geofencing thus creates a virtual defence to secure those corporate devices, which contain confidential enterprise data and aren't expected to leave a certain location/location range, in accordance to the organization compliance standards.

MDM's geofencing ensures devices leaving the geofence are automatically marked as non-compliant and thus, triggers a set of actions - from passive actions such as notifying administrators and/or device users to executing security commands to provide both proactive and reactive security. You can choose to lock the device to prevent unathorized access or even wipe the device data to prevent misuse of corporate data. You can have multiple actions executed simultaneously, when a device becomes non-compliant based on a geofence policy.

Further, with MDM's geofence policy you can have a geofence spanning up to 2 kilometres, ensuring a sizeable region can be used as a part of the geofence based on your specific scenario. Further, you can also schedule for certain actions to be executed automatically as well. Assuming a device is marked non-compliant based on the geofencing policy associated with it, you can choose to wipe the device either immediately or have the command executed after a specified period of time, say after a day or two. 

Also, this non-compliant device can be marked as lost, whereby the device gets locked with the optional message being shown on lockscreen. To know more about mark as lost, refer to this.

To configure geofencing using MDM, refer to this.