JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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.
By default, each submission already has a unique ID, you can find it when you enable the "ID" check box option in your submissions page. Here's a guide on how to view your submissions: https://www.jotform.com/help/269-How-to-view-Submissions
In the submissions page, click the gear icon to open the settings, you can check the option "ID" there, you'll see the submission ID.
If you want to set your own custom unique ID on your submissions, that is possible, here's a guide on how to do that: https://www.jotform.com/help/79-How-to-Add-Custom-Unique-IDs-to-your-Form-Submissions
Let us know if you need more assistance on this.