There is not any Hibernate option in Windows 8 power shutdown menu, until you enable it from settings. The method to enable WIndows 8 hibernate mode is as simple as described in the video embedded below.
Removal of traditional shutdown, restart or hibernate option has puzzled a lot to Windows 8 users. And understanding the concern, Microsoft has added these power options in "Win+X" Menu under Windows 8.1, which we also call "Quick Access Menu."
If you are new on Windows 8, one thing you might have noticed that it is entirely different from previous Microsoft Windows versions. The User Interface is a whole new look to Windows. Thought changes being made to Windows 8 are appreciated a lot, but with these, a lot people are finding hard to use it without going through trouble.