You can play high-definition videos (HD, Ultra-HD, or 4K) in the Movies & TV app on Windows 10.
To enjoy high-definition quality, make sure that:
The video itself is HD or 4K (not SD)
Your hardware (device and screen) can play high-definition (check the manufacturer’s website)
If you're using an external screen, it’s connected using the appropriate cable—HDMI, DVI, or DisplayPort (check the manufacturer's website)
Note: Internet connection speed may also affect streaming video quality.