Starting And Closing a Universal Or Modern UI App
Modern UI apps and Universal apps (which work on any Windows device, including Windows 10 Mobile) are optimized for touchscreens. Although they are started the same way in either regular or Tablet Mode, Tablet Mode uses a different way to close them. In this example, I start and close Calculator from the All Apps menu.
Tap a Modern UI or Universal app to start it.
When you are finished using the app, press and hold the top edge of the screen.
Drag the app downward.
Continue to drag the app window down until it disappears. The Tablet Mode Start menu appears immediately afterward.