How do I restore deleted Messages App on iPhone?

Swipe your home screens all the way to the left to reveal the App Library. Locate the icon for Messages. Press and hold the icon and then drag it to the home screen you want.

Try a Force Restart on your iPhone. Force restart iPhone - Apple Support After it restarts and you log back in, try what I told you again. You need to press and hold the icon and pull it away. I just tried it on my device and it worked just fine.