They seem really stiff and I think I will break them if I try any harder, the car is 2 years old. Any help please, I looked in the manual and it said there is a button but I can’t find it on this particular model.

if mirrors are not electrically folded and u have not folded them for last 2 years, they might be jammed , put some spray lubricant and force to fold them next day.

Electrical folding is an optional extra. They will be stiff but will move with a good shove as they have to in case you hit a person with them.