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.
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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 not possible to set up the form to be limited only to certain users or domains, but if you have your users under the same domain I think you can achieve this via conditions, for example, before to continue to the form you may ask for the email address and if it is under the domain you want to allow then all the fields in the form will be shown.
Here is a guide that will help you to hide / show fields based on other field's answer: How-to-Show-or-Hide-Fields-Base-on-User-s-Answer
Here is a screenshot of the condition that you may add to your form:
Hope this helps.