Qualifications
OT certification requires a master's degree and a passing score on the NBCOT exam, which kinda sounds like a theme park, but really stands for "National Board for Certification in Occupational Therapy." OTs also have to complete a lot of training, or fieldwork during their degree programs (though you won’t actually have to be in an actual field to complete it, which is good news for your shoes). Certification requires at least 24 weeks of practice, ideally in different specialties. It's a lot of work, but afterwards you get to stick "OTR" after your name, to prove you’re a registered OT.
If you crave more letters, you could complete a two year associate's degree instead, to become a certified occupational therapy assistant, or COTA. But you still have to take the NBCOT exam (darn.) Some COTAs complete extra schooling to become a certified OT, and there are degree programs which give them credit for all the stuff they already know.
Certification isn't the final step, though...you'll be expected to renew your license every now and then with classes and seminars. But hey, if nobody updated their skill set, people would still be walking around on wooden legs.