Opening files in external apps Note: Only files can be opened in external apps. Open Qfile Pro on your mobile device. Tap on the app bar. The Device List window appears. Tap a QNAP device to select it. The Folders window appears. Identify a file, and then tap . The file and folder action menu opens. Tap Open in other apps. A system menu appears showing external apps on your mobile device that can open the file. Tap an external app icon. The external app opens the file.