The iPad screen switches to either the portrait or landscape view in response to the way you hold the device. What if I want to lock the screen orientation to one view so that the screen doesn't rotate to another? Easy.
Double-click your iPad's Home button to see a row of icons at the bottom of the screen.
Flick right until you see the Orientation icon (see the screenshot).
Hold the device to the orientation you want and tap the icon to lock it.
To unlock it, tap the Orientation icon again.