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.
I presume that you would like to limit the jotform submissions in case someone already submitted the jotform, avoiding duplication. For this you should take a look at these 2 guides
Do let us know if this is or is not what you were looking for and please let us know if you have any further questions if it is.