The iOS operating system supports user control over screen orientation on your iPad, so you can choose whether an app rotates or not when you turn your device from portrait to landscape mode and vice versa. If you lock rotation in a mode, the screen stays in that position, no matter which way you turn the iPad. If the screen doesn't flip when you expect it to, unlock rotation. If the iPad isn't locked, but its screen still won't turn, try a couple of troubleshooting fixes.
Check the Lock Icon
Check your rotation settings. If you can see a lock icon on the Status Bar at the top of the screen, rotation is locked and you need to unlock it.
Manage Screen Rotation With the Side Switch
The Side Switch on an iPad works as a Mute button or a Screen Rotation control, depending on its settings. If you've set this switch to control rotation, push it up to unlock the feature and remove the lock icon from the Status Bar. Put the switch down to lock rotation again.
Manage Screen Rotation in the Control Center
If you haven't set Side Switch rotation control, use the Control Center to unlock the feature. Swipe up from the bottom of the screen and locate the Orientation Lock -- the lock with an arrow around it. If screen rotation is locked, the icon is highlighted white; tap to unlock it.
You'll see a message -- Orientation Lock: Off -- flash up in Control Center and the lock icon disappears from the Status Bar.
Turn Your iPad Off and On Again
If rotation is unlocked, but you can't change screen orientation, even when using apps that you know should rotate, you may have a glitch on your iPad. You can clear most minor bugs by powering down the device and starting it up again.
To restart, press and hold the Sleep/Wake switch at the top of the iPad until you see Slide to Power Off. Swipe the slider right. When the iPad is off, hold down Sleep/Wake again until you see the Apple logo on the screen.
When the device restarts, open an app to check if it rotates. If it still doesn't work, use a reset. Hold down the Sleep/Wake and Home buttons at the same time for a few seconds until you see the Apple logo. Release the buttons and wait for the iPad to start up again.