Turning your PC into a wireless display on Windows 10

[Windows Central]

If you need to expand your screen real estate, and you don't have a second monitor, you can use another Windows 10 computer, and here's how.
Windows 10 includes a screen mirroring feature known as "Project to this PC," which uses the Miracast standard to seamlessly project the contents of the screen to another computer (or supported devices, such as smart TV and streaming sticks like those from Roku) wirelessly within the same local network.

Full story from the WindowsCentral blog...