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.
It is possible to use Adobe Typekit by downloading your form's source code, once you have the code, you will need to host it on your own website.
Moreover, Here's related guide: http://www.jotform.com/help/100-How-to-Use-Google-Webfonts-in-JotForm. This is about Google Web fonts, but the idea for changing the font is completely the same.
Hope it helps. Please let us know if you need further assistance.