Does Current Flow Through a Transistor From Collector to Emitter or Emitter to Collector?

There is a lot of confusion about which way current flows in a bipolar junction transistor. Does current flow from collector to emitter or from emitter to collector?

And the answer depends on the type of transistor in use.

In an NPN transistor, current actually flows from the collector to the emitter.

In a PNP transistor, it's exactly the opposite. In a PNP transistor, current flows from the emitter to the collector.