To be more precise, you'll need to:
* Consult a repair manual specific to your year and model of vehicle. This manual will have diagrams showing the precise location of each spark plug.
* Look at your engine bay. The spark plug wires will generally be visible, leading you directly to the spark plugs. They're usually surrounded by ignition coils, which makes them a bit easier to spot.
Without knowing the precise year and model of your Ford vehicle with the 4.6L engine, a more detailed answer isn't possible. The location might vary slightly even within the 4.6L modular family due to different accessory placements.