The simple answer is that I find Mozzarella bites work best in a preheated air fryer to 350° F.   Cook them for about 8 minutes, until golden and crispy. And don’t forget to shake them halfway through so they cook evenly.   Cook them in batches if desired or necessary, as space permits, making sure that you only have a single layer of mozzarella bites in the air fryer at one time.   The more complicated answer is that cooking time may depend on what type and brand of air fryer you have, and how big the cooking area is.   The great thing about air fryers is that you can check for doneness at any time. You can pop the Air fryer mozzarella balls back in and cook longer if needed, and you can cook for a shorter time if desired too.