There is no simple answer to the question of what paprika is because there are lots of types of paprika.
Traditionally, paprika is made from red bell peppers. The peppers are allowed to dry and then the stalks and the inside veins are discarded. The pepper fruit and seeds are separated from each other and separately ground into powder. This process is done for different types of bell pepper and the resultant powders are blended to produce the required taste.
Some peppers are dried over fires to give them a woody flavour.
And some pepper powders are mixed with powders from the fruits of other members of the capsicum family to give a paprika with heat (bell peppers, by themselves, have no heat as recorded on the Scoville scale of chilli heat).
So you can get hot, sweet or bittersweet flavours of paprika depending on the peppers used and even where the peppers were grown – the same plants produce different flavour peppers in different parts of the world.
Indian cuisine uses paprika mainly to add a red colour to a dish while the Hungarian cuisine uses paprika a lot to give their dishes flavour, as well as colour.