What are the components of a hollow metal door frame?
A frame that is to have one door would be called a single opening frame and consists of a Hinge Jamb (the jamb to which the hinges would be attached and from which the door would swing), a Strike Jamb (it is prepared for the attachment of the strike plate which is a piece of finish hardware supplied with the lock), and a Head or Header which is the horizontal member at the top that connects the two jambs. A frame that is to have two doors could additionally have a Mullion which is used as a Strike Jamb for both doors when it is used, in that case the frame would have two Hinge Jambs (one on either side) and a Mullion between the doors prepared for the lock strike plates.
