Sagging driver side door

SOURCE: drivers door sags how do i remove pins in hinges

You have to remove the hinges from the pillar post.
This will completly remove the door.
After removing door re-install new hinges
repeat the process in reverse

SOURCE: drivers side door sags towards

Probably your hinge pins and bushings are worn out.Most parts stores sell hinge pin kits and the door spring compressor for removal of the door spring.You may also need some help door is heavier than you might think.

SOURCE: door sags 1996 buick

If you have to lift up on the door and or close it hard--likely a bad hinge --each door has two and you can look into replacing the whole hinge or there are kits with the pin and bushings that can be used to repair a hinge.

Driver door would be most common if car that age and you may just need one of the two hinges replaced/repaired.