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.
You can use one of our widgets for that. The Mobile Responsive widget automatically adjust the display of the form when viewed to mobile devices. You will just need to search it on the widget panel and drag it to your form.
You can also use our new JotForm Form Designer, it has the preview options where you can see how the form will be viewed on different devices.
I hope this helps. Let us know if you need further assistance on this.