the transistor whether PNP or NPN works this way. the applied small base current proportionately controls the larger working current. that is what you call the beta or hfe. each transistor has its own specific beta range as made by the manufacturer and it's up to the designer up to what ratio of base to collector current he will use.
as it is known, the transistor is made with a very narrow base region which is very lightly doped so that the holes are scattered thinly or sparsely so that most of the emitted electrons about 97% or 98% of this emitted electrons are able to cross without falling into the holes. now the electrons that fall into the holes are stuck up at the base region resulting to an increase of negative charge in the base. this is what allows the transistor to throttle the emitter-collector working current. just remember that like charges repel.