I think she is an abused dog...?

if she has no collar or tags and you dont know who she belongs to, you cant rly do anything as far as reporting animal abuse. if the dog doesnt belong to anyone, you can take it in as your own. you should take it to the vet and maybe a groomer if the hair is really bad. if its got matts (nots) they need to be brushed out because its uncomfortable for animals to have.