The Camera App cannot be deleted from iOS devices in any way.
It may have been moved into a folder, or onto a different home screen. If it was moved to a different home screen, you'll need to search for it manually.
You can swipe down from the middle of the screen to bring up Spotlight Search and use it to try to find it. If its in a Folder it will tell you which one.
If you still can't find it, make sure it has not been restricted in Settings->General->Restrictions->Camera.