Print your screen
Pressing this key in Windows 10 copies an image of your screen to the clipboard where you can then paste the image into any application you want such as Microsoft Paint. Pasting an image in Microsoft Paint for example allows you to save the image as a PNG file.
If you don't want to capture your whole screen, you can capture your active window by pressing and holding the Alt key and then pressing the Print Screen key. Alt + PtrScn will copy an image of your active window to the clipboard.
Another useful key combination to help you capture screens on your computer is Windows + PtrScn. This key combination in Windows 10 captures an image of your whole screen and immediately saves it as a PNG file in your Pictures folder under a directory called Screenshots.
If you are using Windows 10 on a tablet without a keyboard, you can also take a screen capture by pressing the physical Windows button + volume down. This method also saves a PNG file into your Pictures folder.