Each door is labeled and removed. The hinges are then removed (also each gets labeled for the exact position). In some cases the location of each hinge is physically marked/scored lightly onto the frame. Labeling everything is extremely important so that an easy re-installation can occur later.
In this photo, Bill Becklund (40+ years of experience) uses a basic battery powered driver to remove things. The Milwaukee make with the light on it helps a lot!