Want a Logoff button shortcut in your start menu? Then follow the steps given below,
1. Press Windows Logo button + R,
2. Type "gpedit.msc" and press enter,
3. Navigate to User Configuration > Administrative Templates > Start Menu and Taskbar and on the right and side and go for the fourth option, "Add Logoff to the startmenu". Double click on it and click on enabled.
4. Then click apply and ok to take affect.