The best keyboard shortcut is to press the “Alt” key at the same time you press “print screen” on the keyboard. Depending on your computer and keyboard, the print screen key may be further to the left and higher up on the keyboard, or closer to the middle. It all depends on the model you have, but generally, it’s towards the number grid on separate keyboards and closer to the backspace on laptop keyboards. This will take a screenshot of whatever you happen to have on your screen at the time. This is saved to your clipboard, so you can paste it in.
To save to your hard drive, use the Windows key and Print Screen key. This will give you a screenshot you can paste from your pictures file.