2010 Ford F-150 4.6l slight vibration when parked/idle?

Thank you for reading. Truck has 45k miles, it has a slight vibration I can feel on the brake pedal and door and console when I'm idle and parked. It's a very slight (in and out) shake/vibration.
It is not bad or violent shaking, but just enough for me to notice.
If I keep the door open and I touch the door I can feel it better.
What could it be?

It could be one or more of a whole load of causes. Such as one or more worn spark plugs, one or more fouled spark plugs (usually an easy fix: take the vehicle for a fast hard run for about an hour, a.k.a. "An Italian tune-up" which burns off any deposits), one or more coil packs which are past their best, a dirty air filter (will reduce the idle speed a little, causing lumpy tickover), a weak engine or transmission mounting (or a weak engine steady arm bushing if your vehicle uses steady bars, most don't), low compression in one or more cylinders (not common, especially at that low mileage). Even silly things like a poor engine earthing (US = grounding) can cause it (again, an easy fix: check the black battery cable makes good contact with the battery post and that there's no corrosion under either end of the engine to body/chassis earthing strap).

Check a few obvious and easy things to eliminate them as causes and after that consider getting a repair shop to read the diagnostic codes

It is a misfire (minor) that will need to be diagnosed. -could be fuel, or ignition issues.