You may also find that clicking Start, Settings, Control Panel, Power Options - the Hibernate tab is missing. What is your situation with the Hibernate tab?
If you find the Hibernate tab, make sure the Enable hibernation option in enabled.
When everything is enabled, pressing the Shift key on the Turn Off Computer menu will change the Stand By button into a Hibernate button.
After you make any adjustments, reboot your system to be sure the changes "stick".