How to use your laptop as a second monitor

[Windows Central]

As long as your PC and laptop support Miracast, you can use your laptop as an external display.
Adding a second monitor to your workstation is an excellent way to expand your productivity, and while the best computer monitors are great for this, you can use your laptop as a second display, too. This is pretty useful, as you can save some money by using a laptop that you already own instead of buying a brand-new external monitor to use. You'll be able to do this as long as both your main PC and your laptop support wireless Miracast connectivity.

Full story from the WindowsCentral blog...