What target do I need to use for Move Forward? Move Forward | Unreal Engine Documentation
I tried with GetAllActorsOfClass and also with a variable with an object reference to a pawn, but is not working
The target is a Pawn. (based purely on the document you’ve linked)
To be honest, I’ve never used this node. I don’t know what type of pawn have you tried but can you try it on a Character and say how it went?
I suspect that it needs the pawn to have a movement component in order for it to work.
It’s weird, it needs the default pawn
Never used it before. Wouldn’t know how.
No, is not working with movement component
Why do you need it in the first place is a better question.
Because there are more blueprints like this that appear to be interesting: Move Up World, Move Right, Look Up at Rate Pawn | Unreal Engine Documentation
Extend the default pawn, it has the Floating Pawn Movement component, it works well with those nodes.
Ah! Research is everything 
Apparently there is a class class ADefaultPawn : public APawn… I honestly did not know that one existed although it is the default when you make a new GameMode.
It has a method virtual void MoveForward(float Val)
@Newest is right