I cannot make my computer hibernate. I altered the settings so that pressing the power button sends the computer into hibernate mode but when I actually press the button, nothing happens. Also, is there any way in which I can add the hibernate option to the drop down menu that appears when I click on the power option?
Yep, the hibernate option in Power panel doesn't work indeed (checked that myself). As it was mentioned here, it's possible to hibernate your PC via
sudo systemctl hibernate command, but impossible to do that via the elementary's power control panel. Long story short, after some discussion the devs have decided to remove Hibernate option from elementary OS.
I simply press the power option in the top right hand corner and select the option "SUSPEND" this puts the pc into hybernation mode to restart just press any key and everything reappears