Per the 2018 Dinghy Towing Guide, page 19, F-150:
Only flat tow a 4WD vehicle by placing transfer case in Neutral and engaging four-wheel-down towing feature.
Put ignition in ON position, but don’t start engine.
If vehicle has ignition key, turn key to ON.
If vehicle has intelligent access, press engine START/STOP button once without pressing brake pedal.
Press and hold brake pedal. Rotate 4WD switch to 2H, then shift transmission into Neutral.
Rotate four-wheel-drive switch from 2H to 4L and back to 2H five times within 7 seconds.
Leave transmission in N and turn ignition as far as it can toward OFF position. If vehicle has ignition key, leave in ignition. If vehicle has intelligent access, press engine START/STOP button once without pressing brake pedal.
See owner’s manual.
(I tried to upload the document but it was too big. You can download from
https://www.motorhome.com/download-dinghy-guides/