Hello Alkriket,
We see you're having issues locating your Messages app. We'd be happy to help out.
There are a couple of ways to help locate apps, so that you can rearrange their location as desired.
If you're using iOS 14 or newer, you can navigate to the App Library, locate Messages in the list here, and then drag it to your Home Screen. Details on App Library here: Organize the Home Screen and App Library on your iPhone
Another option is to head to your Home Screen, and swipe down from the middle of the device. This will give you the Search box where you can type in Messages to find it. Once it comes up here, touch and hold on it to start dragging it. Then, tap on Cancel in the upper-right, while also still holding down on the icon, and then place it wherever you'd like.
Lastly, you can reset the Home Screen Layout at Settings > General > Transfer or Reset iPhone (will be labelled differently for older iOS versions) > Reset > Reset Home Screen Layout. Note that this removes any folders that were set up, icons will be reset to alphabetical order.
Take care.