looking for info on my grandfathers military records WWII Army Ranger?

I am looking for free info or where I can go to find out more info on my Grandfather who was in the Army in WWII. All I know is he was Army, one of the first Rangers I have some pics and more then a hand full of medals. I would like to make a family album but don’t want to go by just hear say
I want to have the facts that go a long side his many medals.I would like to know where I can go to retrieve this information

FRAYNE