Remembering to lock your computer if you step away is the best way to keep your computer and your files safe. An unlocked and unattended computer is a vulnerable computer. Even if you're away for just a few minutes, someone could read your messages, send an email from your account, copy/delete/change your files or steal confidential data.
Below are the shortcuts to lock your screen that will keep your computer secure:
You can lock your Mac's screen by pressing Ctrl + Cmd + Q. This keyboard shortcut will immediately take you to the computer's lock screen and you'll need to reenter your password to get back in. For an even faster lock, press the power button quickly one time.
If you're using Windows, you can press the Windows key + L to lock your screen. You can also press Ctrl+Alt+Del and choose Lock from the list of options just like you do to change your password. If you're not a fan of keyboard shortcuts, you can also click the Start Menu icon, click your username(picture of a person at the top) and then click Lock.