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 believe this widget is what you are looking form, Unique ID widget. It adds a unique ID in your form's submission with the format you prefer and will increment its value per unique submission.
I would also like to suggest that you register an account to us, I see that you are using a guest account. It would be better to register one so that you can manage your forms better.