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 can see that you downloaded the form's full source code. The problem with this method is that the changes you do in the Form Builder will not reflect on form's full source code. You need to edit the actual code on your website in order to add or delete form fields.
Hope that helps. Thank you.