does it need “adjusting” or replaced
No one can really say anything without any information. What do you mean by it “doesn’t work”? I’ll assume it is a handle operated brake. When you pull up on the handle do you get any resistance at all? Or no resistance at the bottom and increases slightly by the time it is all the way up - so that it feels like the brake is on, but it won’t hold the car in place? You need to describe what is going on.
Anyway…the parking brake is a mechanical way of activating the rear brakes on the car - so it isn’t a separate thing that is replaced. It is operated by a cable attached to the mechanism inside your car and running back to the rear brakes. Your cable might be broken anywhere along the way - in which case you need to have it replaced. Or it might be badly out of adjustment - most of the time those adjustments are simple ones to make inside of the car.
When is the last time you had your rear brakes checked? You might also have a problem there as well. Take it to a trustworthy locally owned shop and ask them to inspect.
cig roller gave you excellent suggestions. especially the “take it to a shop” and have it diagnosed.
you could give some more illumination of the operating conditions. have you used it often, or not much. does it hold the car on a slight hill? does the handle work?
more info please
There is not much to that brake. Anyone who knows cars should be able to figure it out quickly if they have access to the car.