Well yeah it will. Hope Im not telling you anything you know already here...
As the offset is the distance between the wheel centreline and the hub mounting face, the more offset you have, the closer into the car the wheels will be. Conversely the less offset you have, the further out the wheels will be. It just depends on the design of the arches and what the suspension is designed to take. You can even go to negative offset where the wheels stick right out!
So spacers can put your wheels further out and reduce offset but the only way to increase it and pull the wheels in, is to have the hub mounting face (on the wheel) actually machined down.