What is the difference between an injector and a carburetor?

The basics of a combustion engine is that it needs to be fed with a fine mix of air and finely dispersed fuel to get a mixture that will burn and make power. the ratio of fuel-to-air has to be just right for the mixture to burn.

The oldest way of creating that was through carburettors. A carb is basically a tube that the engine draws air through, and in that tube, sitting proud in the air stream, there's a nozzle where fuel seeps out. The rush of air, the shape of the tube and the size of the nozzle is what disperses the fuel into a combustible mixture.

( well, these days there are acceleration pumps, chokes, idle nozzles and all sorts of trimmings as well, but the basics still stays.)

An injector is basically a nozzle, an atomizer, like on any spray can. It'll deliver a finely misted fuel spray, when fuel is simply pumped through it.

These days injectors are more common, as they give better control of the fuel delivvery over a wider range of running conditions.