Check the threads on the hinge retaining screws for significant damage. Usually a steel door hinge pulls out once several screws loosen significantly.
Apply a thread sealant to the threads of the retaining screws if the screw threads show little wear. The thread sealant has an applicator in the cap, if using a sealant that comes in a can. If using a tube sealant, squeeze the sealant around the circumference of the threads.
Insert the screws through the hinge and into the threaded holes in the steel door. Tighten the screws with a Phillips screwdriver.
Tap new threads into the steel door with a tap that is the same size diameter as the screw threads. Tapping requires twisting the tap tool into the existing hole until you cannot turn it without significant force. Once you can no longer turn the tap, rotate the tap counterclockwise a couple of revolutions. Repeat until you tap the entire hole.
Continue tapping the holes until each has a new set of threads. Insert new hinge screws into the hinge and thread them into the door mounting holes. Tighten the screws with the Phillips screwdriver.