I’m trying to register my pet and it won’t let me finish I already filled everything out but the bottom that says “promotion code” cuz I don’t have that

You don’t need to worry about the “promotion code” field if you don’t have a code. Just leave it blank and continue with the registration process. If you’re still having trouble, please don’t hesitate to contact us at petlink@petlink.net, and we’ll be happy to assist you further.