Apple iPad screen will rotate between landscape and portrait mode if you manually rotate the iPad. By default, screen will automatically rotate as and when you rotate the iPad. You can disable this screen rotation and set it to stay permanently in either landscape or portrait mode while using iPad screen rotation lock feature.

A locked icon will appear in status bar when screen is locked through Screen rotation lock button. You can slide the lock switch up to unlock and enable screen rotation on iPad (the default setting). Simple, isn’t it?