To enable geofencing on an Android device, first ensure the device has internet connectivity, Wi-Fi access, and location services enabled. Then, in the Esper Console, navigate to the Geofence section and create a new geofence by clicking "New Geofence". Define the size of the geofence, which is a circle that can range from 100m to 10km, and set its center using an address or map view. Next, assign devices to this geofence and specify the action to be taken when any assigned device leaves the geofence, such as locking them, having them beep, or both. This functionality is useful for various use cases like tracking fleet locations, ensuring devices stay within a designated area, or monitoring device location in real-time.