Lock Computer Screen Automatically
This article applies to: Secure Your Computer and Mobile Device
Unless your computer is in a secure space that is accessible ONLY BY YOU, you must run a screen saver that will automatically lock your screen after 15 minutes of inactivity and require a password to unlock it.
This is necessary to prevent an unauthorized person from being able to see sensitive information or exploit access to your computer in your absence.
For instructions, see how to set your screen to lock automatically for: