I can remember having to do this in the games tutorial, but I forget the button. I don’t see it on the controls option at the bottom. Could have sworn it was L1 or L2, but neither of those buttons seem to do it. Been getting my ass handed to me so I need to be able to block attacks. Dodging doesn’t work as well.
This is a bit of an awkward game control since the button to block and parry is also mapped to other actions and depending on what is happening in game, a different action may be used. To parry and block in The Witcher 3, you use L2, but it can only be done when you are in proper combat. Just becase you have your sword out, doesn't mean that you can actually block.
Blocking isn't a particularly effective combat mechanism in this game anyway. It only really works against other enemies that have swords or typical human weapons. Most monsters can break your block and stagger you, even if they are low level, weak enemies. Dodge and roll is by far a better method of dealing with enemy attacks in this game. However, to answer the question, is what you need to use to raise your weapon in order to defend against enemy attacks in The Witcher 3.