You should also avoid cleaning the litter box if you are pregnant, but if you must, you’ll need to wear gloves and wash your hands very thoroughly afterward. You’ll also want to thoroughly clean the box daily to avoid the risk of toxoplasmosis.
Typically, cats tend to prefer to use an uncovered box. While some people might believe they prefer the privacy of the covered box, in the wild, kittens never willingly go into enclosed spaces where they might encounter a predator. Your cat might have a different preference, but if you currently have a covered litter box and your cat’s training isn’t going well, you might want to try uncovering it. On the other hand, if your cat isn’t eliminating in the litter box and it’s currently uncovered, they might have a preference for privacy, and you could try giving them a covered litter box to see if that helps them.