Motor oil

Check the owner's manual for that. Otherwise just keep adding until the level on the dipstick is anywhere between "Min" and "Max". They don't use "Add" and "Full" anymore because it's normal for engines to use a little oil between changes and they don't want people complaining about the level going down. That's why even if your level goes down before the next oil change, as long as it stays above the "Minimum" mark, it's okay.

Dealer can help you or look at the salvage yards. Mechanics never bother to look it up and they can't memorize every car model. They just go by the dipstick.