Since Facebook does not include third party apps on mobile, mobile links are the one way to access tabs on mobile. To add mobile access to a tab, use the shareable link provided in the top right area of the editor.
Below the image are three ways you can make your tabs accessible on mobile devices using this share url. :)
1. Have your Call to Action Button on your Facebook cover photo link to your mobile tab. Instructions can be found here: bit.ly/fb-page-call-to-action. (Go ahead and use the mobile url for all the links these instructions mention.)
2. Posting and pinning a status to your page wall that includes the mobile link to your tab: bit.ly/fb-page-pin-post.
3. Add your mobile enabled link in the description area of your cover photo.
Also, the name of mobile url can be customized with tinyurl.com
To customize the image and headline of your post, first paste in your bit.ly link into the post area. Then upload your own image, and click on the bit.ly headline in bold below the image to add your own custom headline.