Live Guidance in the app provides on-screen suggestion popups, as well as bounding boxes as suggestions for where to concentrate the subject of a photo or video. It is on by default, but if it needs to be turned off, that can be done in the app.
While the camera is open in the app, click the Overflow menu (...), then Live Guidance: Off.
To turn Live guidance on in the app, click the Overflow menu (...), then Live Guidance: Off.