What the singers who sing in the streets are called?

Is there a name or an expression is used to name the singers who tours
around singing in the streets? Singers like Hannah Trigwell, she
started singing in the streets of England.. so what is the name to
call the new comers of singers who sing in the streets as beginners?
My mother tongue is not English so forgive my stupid question if there
is nothing at all called like that :)

Thanks a lot for help :)