If you moved from Windows 7 to Windows 10, you may not be able to find where to log off your session. Windows 10 has relocated the log-off button to within User in Start Menu. See the below:
These steps illustrates the changes to log-off process from Windows 7 to Windows 10:
Windows 7: Start Menu > More options next to Shut down > Log off
Windows 10: Start Menu > User > Sign Out
Lock button is re-located in same location as Sign-out in Windows 10.
All done! You can now sign out in Windows 10!