The center caps get grease so they don’t make noise, you can use anything you like on those, I have used wheel bearing grease because it's sticky. Door latches and hinges I use white lithium grease. I usually spray the latch with penetrating oil first, then the white grease.

The door latch is the part that is visible when you open the door (on the door side in the jam). It’s the part that makes contact with the striker in the door jam to latch the door closed.