Cats are by far the easiest animal to potty train, particularly if you get them as kittens. You set up the litter box, sit them in it every few minutes until they poop and/or pee in it, and voila! I’ve never had to do more than that for a kitten.
Now puppies, on the other hand, are a huge pain in the ass to potty train. It took several months to stop our pup from pooping in the house when it rained.