The rule of thirds is a principle in photography that involves the imagined splitting up of a shot into nine boxes: three up top, three in the center, and three at the bottom. Studies have shown that the human eye is drawn to one of the intersection points of these lines in photographs. By placing points of interest along the lines and intersections of the grid you’re making your photo more appealing and balanced to viewers.
You can set up your iPhone camera to display a grid when taking photos or video.
To do so, open your Settings, scroll down and select Camera, and toggle on Grid in the Composition sections.