Lost my message icon, how do I restore it. iPad Air

Use the search feature to find it on your iPad.

Touch any empty area of a Home Screen (anywhere except the extreme edges or the corners of the screen) - and swipe downwards to reveal the Search dialogue at the top of the screen. Type “Messages” in the search dialogue; if still present on your iPad, you’ll see the icon and its current location.

My pleasure to help.

You may find the iPad User Guide for iPadOS has lots of other useful information. Here are direct links to both the downloadable and online versions:

https://help.apple.com/epub/ipad/en/

https://support.apple.com/guide/ipad/welcome/ipados

I hope you find these resources to be equally helpful.