If you’re a beginner, use the simplest possible digital camera with a built-in flash. If your phone has a good, built-in camera — and most do — use that.
If you’re buying a ghost hunting camera, make sure it has a flash. Ask if it’s designed to take good pictures in low light conditions, too.
Other than that, you don’t need anything special.
Later, you can explore more specialized cameras. Those can include infrared cameras, heat sensing cameras, and cameras with clearer glass lenses.
(Many budget cameras have plastic lenses. The quality can be fine, but a good glass lens might produce far crisper results. Then, you can identify normal — but odd — things in “anomalous” photos.)
You might also test remote flash lighting and other devices. Still, beginners probably won’t need that equipment for at least a few months.