Below is an image of a cabinet hinge... The adjustment screw in the front adjusts the tilt of the door.
Best way to learn how it works is to move the screw back and forth... From time to time or from a change in season, because wood expands and contracts, you may need to use this screw to keep your doors in alignment.
The screw below adjusts the door up and down.
The adjustment screw in the photo below moves the door in and out