Gas filler lock

Hi:

It sounds like you have a capless filler tube. Most of these vehicles came from the factory with a specially designed funnel to add fuel with a fuel can. Watch this video

https://www.ford.com/support/how-tos/more-vehicle-topics/fuel-and-fuel-economy/what-is-the-easy-fuel-capless-fuel-filler/#: :text=In%20the%20event%20you%20need,Easy%20Fuel%20capless%20fuel%20filler.
As far as the location, check around the spare tire area. It should be there. If not, check under the front seats.

Let me know.

Joe