When you install a pre-hung door, you move the jamb in and out to meet the door when closed. Cut the nails behind the jamb at the top and on the strike side, close the door and move the jamb to the door. Make note of where the jamb is in relation to the rough opening, check the reveal, shim tight at the end of the top jamb and use one nail in the strike side jamb near the top. Close the door and check. The one nail will bend if you need to adjust. Put in a second nail and check again and so on. Don't skimp on the shims.