We call carbonated water szóda (soda), the word used in English too, but has other meanings when it comes to drinks, for us it's just this.
Back in the days they distributed the siphons with coaches, carts. Then they figured out how to make carbonic acid cartridges that people could fit into the siphon and make carbonated water themselves. Basically all households had these appliances (there were one type for making whipped cream too, although I don't think carbonic acid was used for that), and people could get the "cartridges" (probably I'm one wikipee search away of knowing the actual name of these) in groceries. But around 2000AD they started to go out of fashion and many started to buy the soda in shops. Carbonated mineral water also added to the decline. In 2018 the production of cartridges ended, so noone can make soda this way anymore. Well, I'm not sure, maybe a new factory was opened somewhere since then.
I think the advantage of soda over carbonated mineral water is that it's way stronger.