How often do you bathe a Old English Sheepdog she is 6 months old?

And is there a special soap out there I can buy to make their coat shinier for sensitive skin and long hair. I really want her to look amazing because I would like to see her grow up as a beautiful dog. If you know of how often to bathe and brush her also if there is a special shampoo for sensitive skin that makes their coat shiny, tangle free, and it works on long fur.