You can add actions specific to the devices (Web / Mobile) on which the application you developed works.
Click on the element you want to add Device actions to and make it selected. Go to the Properties panel and select the action you need under the Device heading from the list opened with + Add Actions.
For example, for a mobile app, you can use the Phone Number Call action to make a phone call to the number in the app.
Device actions are actions that can vary according to the features of mobile and web applications. Download File and Upload File Device actions are available in web applications, but not in mobile applications.