Hibernation is a power-saving state that allows your setup to quickly resume working.
It saves your work and turns off the display.
When you start your system again, it returns to the same state as when you hibernate it.
Check out how it’s possible for you to turn on or off hibernation option in Windows.
Hibernate is a power saving mode that allows your gear to quickly resume from being powered off.
When you start up again, Windows loads faster because it doesnt need to check all of your hardware.
How hibernation is useful?
Also know about difference between hibernation and sleep:sleep vs hibernation.