How to use Apple’s AirDrop over a cellular connection
To enable cellular data on the other person’s iPhone or cellular-equipped iPad, go to Settings, select General, tap AirDrop, and then turn on the switch for Use Cellular Data. While you’re here, make sure AirDrop is set to either Contacts Only (if you’re in the person’s contact list) or Everyone for 10 Minutes (if you’re not in the list and want temporary access).
To enable cellular data on the other person’s iPhone or cellular-equipped iPad, go to Settings, select General, tap AirDrop, and then turn on the switch for Use Cellular Data. While you’re here, make sure AirDrop is set to either Contacts Only (if you’re in the person’s contact list) or Everyone for 10 Minutes (if you’re not in the list and want temporary access).