NPN vs PNP Transistor Wiring
What do you mean by "before the transistor" and "after the transistor"?

In both cases shown, the load is connected to the collector of the transistor.  The circuits may look different, because an NPN and PNP transistors work with opposite polarity power supplies.

An NPN transistor works with the emitter as the most negative terminal, and the collector positive, while a PNP transistor wants the emitter to be the most positive terminal, and the collector most negative.

If you have a simple NPN circuit, you can change the transistor to PNP and invert the power supply polariity, and the circuit should still work.