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.
Please take a look at our Unique ID widget here: http://widgets.jotform.com/widget/autoincrement
You can add it to your form and then configure it to create a unique ID for each submission.
Please check it out and let us know if this is what you're looking for.