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.
Yes, that's possible. You only have to hide the field (right click > hide field) or use hidden box widget in the form builder if you don't want users to see it or if you want it to be the admin field. Then, you can edit the hidden field when you edit the submissions in your form submissions page.
This guide explains it http://www.jotform.com/help/194-How-to-Add-a-Submissions-Status.
Hope this helps!