How does the underfloor heating work?

Hello, Can someone tell me how heating with underfloor heating generally works? Not now about the technology in general, but rather regarding electricity, gas, etc.? I assume it runs on electricity? Isn't that pointless, considering rising electricity prices? It hardly runs on gas or oil, does it?

Or does the water, which is then heated, flow?

Question answered myself ;-)

Normally, water is heated and run through the floor.
The advantage is the incredibly large heating surface, which allows the use of low water temperatures in reasonably well-insulated houses.

Ok, thanks.
Yes, the idea came to me shortly after sending it :D

But there are also electric underfloor heating systems, e.g. for bathrooms in old buildings during renovation, I know that. The heating was installed directly under the tiles.