Why my page is not supporting in Mobile?

I have created a form and I attached this in my facebook page. but problem is this form is working only from pc. I also need this form available in mobile device. but thats not working on phone. How can I fix this?

Unfortunately, Facebook does not support Tabs on the mobile website and custom page tabs cannot be shown on mobile devices.

You can take a look at the following bug report on Facebook:

https://developers.facebook.com/bugs/435173473172584/ 

There are specialized companies who have dedicated their services to enabling Facebook tab pages to be shown even to mobile users. Examples of these companies:

http://blog.woobox.com/2011/12/woobox-short-urls-now-auto-redirect-to-tab-and-mobile/ 

https://www.tabsite.com/blog/mobile-solution-for-facebook-page-tabs/ 

http://blog.thunderpenny.com/2013/01/tabs-on-mobile/ 

You may want to look at one of them as your solution to working around the limitation by Facebook, to have your forms on Facebook accessible to mobile users.