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.
Please be noted that Page Tab apps are not supported on mobile devices by Facebook's Platform: https://developers.facebook.com/bugs/435173473172584/
A workaround for now would be to use third party websites that offer a mobile version for tabs. You can also your page direct URL as well. Please check the following guide and look for (FAQ - 1. The page tab does not appear on mobile devices?) section: http://www.jotform.com/help/82-Adding-Form-to-Facebook-Custom-iFrame-App