Ideally press ( to get excess liquid out of tofu), Dry, then can do as you would do anything else you would batter.
You can avoid the egg, but I find the egg to be best at allowing the batter to adhere to the tofu.
If you're just looking for a crispy coating, you can coat with corn starch and fry. Will give a nice crispy texture. For this I usually just Press the tofu, pat dry ( dont have to go crazy this step as long as not dripping wet), then I put the cubes in a container with corn starch, close the lid, then lightly shake until all surfaces covered. Fry in oil til crispy. You can also season the starch a bit with onion powder, garlic powder, ginger powder ... which ever would go Witt the dish you were putting it in.