My IPhone texting app has disappeared.

The Messages app is a native iOS app and cannot be deleted. Check your other home pages and folders to see if you can locate it. If not, then go to Search and type in Messages and see if it shows up. If it does, see if it lists a folder to the right of the listing.

If you cannot find it, then try a reset. Hold the sleep/wake and home buttons together until you see the Apple logo and then release. The phone will reboot. If you still cannot locate it, then go to Settings>General>Reset>Reset Home Screen Layout. That should bring it back.