Water for 6 month old ??

My baby had her 6 month checkup yestuday and the doc gave us the ok to start water she said to just boil tap water or get nursery water with added fluoride but I can’t find that anywhere I think target discontinued it and I can’t find it at meijer and I don’t want to have to boil water everyday is there any type of normal water baby’s can have like bottled waters if so what kind should I get spring, mountain, distilled and what brands? If not I might just end up buying a kettle but if anyone uses bottled water for there young baby’s please let me know what kind and brand I should get !?