Device Preview allows you to preview and edit content in Experience Manager as it is displayed in a handheld device such as a mobile, smartphone, or tablet.
Viewing content in a device You can preview a Component or Page as it appears in a device in Experience Manager. You can also view an external URL in a device.
Rotating the device orientation Many devices allow users to rotate the device to view the content in landscape or portrait. Similarly, you can rotate the view in Device Preview.