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.
Unfortunately signature and upload files and not available inside of fillable PDF. In case that file upload is added to your form it will be hidden at this time on the PDF files since you can’t transfer file attachments to our servers via a PDF.
And considering widgets like signature, it require extra scripting and are loaded from external resources so at this time they are not available.
For more info about restrictions in fillable PDF you can find inside of this article:
Hope this will help. Let us know if you need further assistance.