Does a 2004 ford f150 use front or rear brakes to stop when applying the pedal? I would assume the rear pads and disc are for the e brake correct? And the front would be for the normal driving braking?

 

During normal braking all four brakes are used with the fronts doing most the work due to the weight of the vehicle going forward.
Parking brakes use the rear brakes on every vehicle I have ever seen.
2004 F150 is a little old for me but I'm pretty sure the rear brake use a top hat design disc/drum where the normal hydraulic brakes are disk and the calipers are visible, but the parking brake is a drum style that applies force to the inside of the rotor which is machined to be a drum.
This is visable if you remove the rotor.
The reasoning being its much easier to make parking brakes with drum brakes then with calipers, now a days its done in calipers regularly though but they are more complex.

 

The fronts account for about two thirds of the braking force.