Unwanted black box and white circle in center

My wife and I both have iPad 12.9. Yesterday a small black box with a white circle in the center appeared on my wife’s screen. It can be moved anywhere on the screen. If taped, it brings op items one can access. How do you get rid of this box. I have tried everything I know in Settings but have found nothing to shut it down. I tried some oils comments on this help location. ie: Zoom, and others but they are all turned off. Looks like a spy camera in disguise. It is always in the way and must be deleted.