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.
You can enable autofill on the form so that user can complete the long form later.
Enabling Autofill feature will automatically save the form's field values locally (browser local storage) until the form is submitted. This way, your users don't lose any single data if they accidentally close or reload their browser while filling the form. Please take note that they need to use the same browser in order for the saved field values to autofill in the form.
Please follow the instructions provided at https://www.jotform.com/help/227-How-to-Enable-Auto-Fill-on-Forms
Hope this helps.