It would be a single-hand cast spell that the player can cast it on their summoned creature (Undead, Daedra, etc.) and then re-cast it at a location. The summoned creature would then move to the location. If the creature enters combat on the way to said location, then they would break the command and attack. Even if it's two spells - one in touching range to select the summon, and a ranged one to determine the location; that works as well.
The spell would only work on creatures summoned by the player and would be under the school of Conjuration (Novice level) at low cost of magicka.
I was actually really surprised that I could not find anything this simple. It's literally a "you, go here" spell for summons who currently follow players indefinitely with no depth. The functionality is already present in game with the "Hold E to command follower" feature. I would just like to have that in a spell form for an undead follower/atronach.
Thank you for your consideration.