What I did know was that I loved her books. She's perhaps best known for Howl's Moving Castle, which was adapted into a film of the same title by Hayao Miyazaki. Both of which are quite wonderful. Or perhaps you've run across her silly, smart, and delightful Dark Lord of Derkholm, which won a Mythopoeic fantasy award (her remarks come after Gaiman's), which manages to both skewer fantasy tropes and tell a wonderful story, all at once. My first introduction to her was, I think, through her Dalemark quartet, which I must go and re-read, because twenty years have made the details fuzzy -- but I loved them, and loved them enough to go and read anything of hers I could find. Which of course led me to the utterly delightful Chrestomanci books, of which my favorite is probably The Magicians of Caprona, though it's very hard to pick a favorite -- and many more.
Jones published more than fifty books, and I have read them all, I think, some of them more than once. They're clever, and funny, and sweet, and utterly charming; they hold up to re-reading. And if all my books weren't in storage, that's exactly what I'd spend today doing, reading her books, over and over again. I'm sure she's influenced my own writing, in ways I don't even know.
Such a loss. And such a legacy.