You can quit or close the VMware Horizon app just as you would any Windows Store app.

You have several methods for quitting the app.

If you use an external mouse device, point to the top of the screen until the VMware Horizon title bar appears, and click the X at the right end of the title bar.

Tap the top of the VMware Horizon app and drag it to the bottom of the screen.

Use the Alt+F4 key combination.