Bathing Bun

I know buns don't need to be bathed, but should mine need it, what can I used soap wise to clean her. Is there anything for fleas etc?

Whether they need it or not is 1 thing. Should it ever be done? No. We've seen people on here whos rabbits have died as the result of a bath. Just don't do it. Your rabbit shouldn't ever get dirty enough to need one, if its just dirt it will fall off, moult out, or they will clean themselves. If its urine or feces, then take them to the vet as this shouldn't be happening.
G0 to the vet and get Revolution 18mg/kg or advantage if there is a flea issue.