how do you tighten door latch on body of car?

SHOULD TAKE AN ALLEN WRENCH FROM PARTS STORE

It's not anallen wrench it's a star wrench and yes you will have to get from a parts store but not all carrie them beacuse it's a mechanics tool just to make you pay more. I've used a straight head screwriver must be the right size or will strip it but it has worked better than $ 65.00-150.00 that I don't have.

Try a Torx bit with 3/8" drive socket and ratchet, not sure of the bit size.