Can someone tell ne what i need to do for my dog she scratches her area all the time?

Hello my name is Brandy and i have an adult female who starches her area almost all the time.Im thinking that it is both the area and the pee pee area.I am just wanting her to feel better.I was told it could be worms or fleas that have been ingested by the dog. i don't know which one it is.So how could i myself know and figure this out?