Imagine you're making a pot of tea, but instead of steeping leaves, you're boiling water and catching the steam. That's basically distilled water. Distillation is the process of boiling water until it turns into vapor, then cooling that vapor back into liquid.
Here's the kicker: when water boils, most of the impurities—like minerals, salts, and even bacteria—get left behind in the pot. So what you catch in your collection jar is almost pure H₂O. Some folks call it "the cleanest water you can get," and they're not wrong.
I once tried making distilled water in my kitchen just for fun. I ended up with a sad, tiny puddle of water and a burned pot. I left the experiment to the professionals after that.