How do witches get their titles?

Reading through wyrd sisters and started thinking. Granny Weatherwax doesn't have any children much less grand children of her own although I concede that everyone's like a child to her. Nanny Ogg makes sense given her queen-dom of Oggs. But then you get Goodie Whemper and Goodie Filter. Looking at Tiffany you've got Miss Tick which granted... mystic. But other Miss [name] witches are in other books, right? And then you get a few Mistress Such-an-Suches. There's the obvious Mrs. Ms. Who don't really use titles but as previously mentioned, some do use Miss as a type of title, no?

Do they just give themselves certain titles that suit the names or are they given by the other witches?

Thanks!