Do you want to clean it or add it to the water? If you empty the tub, you can clean it with bleach as long as you rinse it well. Do not add it to the water. You can use chlorine products or other gentler chemicals especially made just for hot tubs.
No you cant put bleach in a spa its not ideal to the only type of bleach is chlorine that you could put in a spa. But other than that no you shouldnt because that can become dangerous to the people that come to the spa. hope i helped with you question.