Change or lock the screen orientation on iPhone
When you use supported models in landscape orientation, some apps have different layouts. These apps include Mail, Calendar, Messages, and Photos.
Note: These different layouts aren’t available when Display Zoom is enabled.
Lock or unlock the screen orientation
You can lock the screen orientation so that it doesn’t change when you rotate iPhone.
Open Control Center, then tap .
When the screen orientation is locked, appears in the status bar.