Create a shortcut by right-clicking the desktop. On the pop-up context menu, choose “New“, then “Shortcut“. Then copy and paste this in the program location box:

rundll32.exe user32.dll,LockWorkStation
Click “Next”, and enter a name for your new shortcut, such as “QuickLock” or whatever. When you double-click that shortcut, you’re logged off the network, and has the same effect as logging off. All running and open programs remain intact upon logging back in.

or….

Press the Windows Logo and the L keys simultaneously.