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.
Yes, forms allow file type upload restrictions. Inside of Form Builder select File Upload field and click on Extension option. There you can set extensions of your File Upload field.
More about upload field allowed file types you can find in this article:
I have created demo form and I set pdf to be only allowed extension of file upload field.
Hope this will help. Let us know if you need further assistance.