What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
That's probably happening because you're viewing it with Facebook page active. You should switch first to your main Facebook account before clicking "Add Facebook Tab" button. I would suggest to logout from your account first. Relogin but this time don't switch to your FB page yet. Go to the form builder and add your form to FB. You should see list of FB pages where you want to add your form.
If you have further questions, let us know.