The snipping tool is a little program on Windows 7 and later that very useful to capture a screen.
How to Install The Snipping Tool
If your computer still not has the snipping tool you can install it easily by
How To Use The Snipping Tool
To use snipping tool is easy, first launch the app by typing snipping tool on the search bar and press enter key. You will see above picture, click the New button, the screen become grey and the curson become crosshair.
Click (hold) and drag the cursor to the area you want to create the screenshot, release the mouse button when finished.