When you click the power menu, you will see for Sleep, Shut down and Restart, no Sign out button is there.
There is no Sign out in Power menu |
The location of Sign out button in Windows 10 (also in Windows 8.1) is not in Power menu, but in User menu, You can see the user menu (user icon/or your profile photo if you already use) is above the Power menu.
You will see Change account setting, Lock, or Sign out.