What does a wormhole do?

Excuse me, I've heard of this term 'wormhole' quite often in the realm of theoretical physics and cosmology, but I'm still a bit hazy on its exact function. Could you please elaborate on what a wormhole actually does? Is it some sort of bridge connecting two distant regions of space? Or does it have a more complex role in the universe? I'm really curious to know more about this fascinating concept.