Sometimes a car door is out of alignment because someone hangs on it. Other doors with alignment problems are just showing the signs of wear and tear. It's possible to realign a car door without too much trouble.
Inspect the car door when it's open. Make sure the rubber seal is intact and that it hasn't bunched up causing the door to be to out of alignment.
Close the door. Run your finger all the way around the door jamb. Look for gaps. This indicates where you need to realign the car door. Step away from the car and visually inspect the way the car door aligns with the car's body.
Open the door again. Inspect the striker plate. Make sure it's in the proper location.
Inspect all of the bolts holding the door in place. Note any that are showing signs of wear and tear. Purchase the proper bolts and then replace them.
Loosen the bolts that hold the door in place. Don't remove them unless it's to replace a broken or worn bolt.
Tighten the bolts again. Make sure you tighten them evenly. Periodically close the door gently to see if this is helping to realign the door.
Assess if one of the door hinges is bent. If it's, place a block of wood on it. Gently close the door with the wood in place until the wood pinches. This helps straighten the hinge. Continue doing this until the door aligns properly.