Specifically talking about municipal tap water
In: 2
When you boil fluoridated water, the water gets very hot and turns into steam. The fluoride that was in the water doesn’t like the heat, so it stays behind in the pot or kettle when the water turns into steam. So, the fluoride does not go with the steam, and you won’t be breathing it in when you boil fluoridated water.
Not much.
If you boil off the water entirely, you’ll get a little bit of fluoride in the resulting minerals (which, in most places, will be deposits of various soluble minerals like calcium carbonate). But there’s really not very much fluoride in fluoridated water – about a milligram per liter, or about 1 part per million by weight. So even boiling off an entire pot of water will only result in a few (EDIT: milli-)grams of fluoride minerals.