Bees start making honey, which is their food, by visiting flowers. They collect a sugary juice called nectar from the blossom by sucking it out with their tongues. They store it in what's called their honey stomach, which is different from their food stomach.
When they have a full load, they fly back to the hive. There, they pass it on through their mouths to other worker bees who chew it for about half an hour. It's passed from bee to bee, until it gradually turns into honey. Then the bees store it in honeycomb cells, which are like tiny jars made of wax. The honey is still a bit wet, so they fan it with their wings to make it dry out and become more sticky. When it's ready, they seal the cell with a wax lid to keep it clean.
So that's how bees make honey. They don't make very much of it, though. It takes at least eight bees all their life to make one single teaspoonful. Fortunately for us, they usually make more than they need, so we can have some, too.