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.
Do you want to enable to users to modify your form or to create login form where user will first login before using your form?
With JotForm it is not possible to create login forms. In case that you want to achieve that maybe you need to create some custom functionality. E.g your site will have JotForm embedded inside of site but no one can access it before login. This login functionality need be made additionally by some developer.
In case that you want to enable that someone else can modify your forms inside of your account you can create subuser account and share forms with that users. To find out how to do it, you can read this article:
Hope this will help. Let us know if you need further assistance.