Portrait orientation lock is a feature that allows you to lock the screen orientation of your iPhone or iPad in portrait mode, preventing it from rotating when you turn the device. Here are some key points to keep in mind:

• Many apps give you a different view when you rotate your device. For example, if you open an app like Safari in portrait mode, the screen will look different than if you turn your device to landscape mode.

• You can lock the screen orientation so that it doesnt change when you rotate your device. To do this, open Control Center and tap the Portrait Orientation Lock button. When the screen orientation is locked, a lock icon appears in the status bar (on supported models).

• Some apps dont support rotation, so your screen might not rotate even if Portrait Orientation Lock isnt turned on.

• If you want to turn off Portrait Orientation Lock, simply tap the button again in Control Center.

Overall, Portrait Orientation Lock is a useful feature if you prefer to use your device in portrait mode and dont want it to rotate when you turn it. However, if you like to use your device in landscape mode for certain apps, you may want to keep the feature turned off.