Check to see that the weatherstrip, which mounts to the body opening, is pushed on and tight. The weatherstrip has metal inserts which permits you to squeeze and tighten the application groove, if it is loose.
Check the rubber “accordion” conduit that runs between the A-pillar and the door, by the door hinges. See that it is properly seated at the A-pillar (it is a press fit). If it is loose or dislodged, it can allow water to enter behind the inside floor kick pad, and onto the carpet.
Check the door check-strap (also by the hinges). There is a small donut rubber gasket on the plastic strap arm that seals against the A-pillar, when the door is closed. There is also a foam gasket inside the A-pillar, where the plastic check-strap arm enters, when the door is closed.
See if the bottom door drain openings are clogged. Ford installs a small plastic push-in piece, in the door drain openings. You can pull them out and see if water is inside the door (and the drain openings are clogged - which can be cleared with the non-clasp end of a plastic zip tie).
