Automatically lock your screen
When you leave your computer, you should lock the screen to prevent other people from using your desktop and accessing your files. If you sometimes forget to lock your screen, you may wish to have your computer’s screen lock automatically after a set period of time. This will help to secure your computer when you aren’t using it.
When your screen is locked, your applications and system processes will continue to run, but you will need to enter your password to begin using them again.
To set the length of time before your screen locks automatically:
Go to the desktop and start typing Screen Lock.
Click on Screen to open the panel.
Make sure Automatic Screen Lock is switched on, then select a length of time from the Automatic Screen Lock Delay drop-down list.
Applications can present notifications to you that are still displayed on your lock screen. This is convenient, for example, to see if you have any email without unlocking your screen. If you’re concerned about other people seeing these notifications, switch Show Notifications on Lock Screen off. For further notification settings, refer to Notifications and the notification list.
When your screen is locked, and you want to unlock it, press Esc, or swipe up from the bottom of the screen with your mouse. Then enter your password, and press Enter or click Unlock. Alternatively, just start typing your password and the lock curtain will be automatically raised as you type.