If your horse is food motivated, that's the easiest way.
I've taught hug, where the horse wraps its head around you. Kiss, which involves trusted that your horse will lick your face and not bite it. Shake, you use a leadrope to pick up the leg after you say "shake" and then give a treat- usually only takes a few days.
My friend taught her baby, Ritz, to lie down, roll over, fetch, come, and sit (sometimes). Ritz is basically a very large dog. Horses are really smart, they'll learn anything.
I don't like a full bow though, it hurts their knees.