I just got I beta fish named star fire(star for short) and I don't know what kind of water to give him some people said that if you boil it and let it cool to room tempeture it will be okay for the fish but I'm not enterily sure please help!

The best way to treat water for a Betta fish, and any fish, is to use a water conditioner to remove chlorine and chloramine and to neutralize heavy metals that may be present in the water.
You can also allow water to sit out in an open container like a big bowl or bucket for 24 hours and the chlorine will evaporate making the water safe for the fish.
Good luck.