Does anyone know if u can put a sync 3 from a mustang into a 2015 f150 both have voice nsvigation

 

Yes you can. They are both standard mount screens so it will bolt in fine. You will need to re-program the SYNC 3 APIM to your truck.
If you want to use Apple Carplay - you will need to change your USB hub to the updated SYNC 3 one, and buy an adapter/splice the wires to the new hub.

You can program the APIM yourself using Forscan, or there are people who will do it for a fee.

If you want to learn how to program it with Forscan, here is a good tutorial to get started:
https://docs.google.com/document/d/1...gF1wxIqxY/edit