Screen Portrait Orientation mode displays content in landscape (horizontal) or portrait (vertical) and isn't available for all apps. Simply turn the device to change the view.
Access the Control Center by touching the bottom of any screen then dragging upward.
For the iPhone X and newer models swipe downward from the upper-right corner of the Home or Lock screen to access Control Center.
Tap the Portrait Orientation icon to lock or unlock screen portrait orientation.
When the icon is highlighted in white, the screen is locked into portrait orientation mode.
The Control Center screen may vary slightly depending on the device model.