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.
Unfortunately it is not possible to convert a form into a downloadable app. Although you can still add the form to your phone's homescreen. Simply follow this guide to learn how: How to Add Websites to the Home Screen on Any Smartphone or Tablet.
If you want to create an app, I have found several website that can help you create an app:
Do let us know if you need further assistance.