Lost icon on iPhone

You can't delete the camera, app but you can turn it off in Settings > Screen Time > Content & Privacy Restrictions > Allowed Apps

Turn Camera on there.

If you can't find the camera on your iPhone, you can search for the camera using Spotlight. Pull down from the center of the screen on your home screen, then type in "Camera" to search for the app.

You can also launch the Camera app by swiping from the right edge of the lock screen or Notification Center, or you can use the camera from the Control Center.