Muggie Maggie is a 1990 children's novel by Beverly Cleary (whom you likely know from Ramona Quimby fame).
One day after school, third grader Maggie mentions to her parents that they're about to start learning cursive. Her parents are unimpressed, so Maggie, feeling obstinate, insists she's not going to bother learning it at all. She can print or use the computer, after all.
The story is then just 96 pages of Maggie refusing to learn cursive, and her teacher ultimately tricking her into learning after all*. Along the way, she mucks up her signature such that her teacher reads it as "Muggie", earning her the titular nickname. (It's an insignificant event that hardly warrants a title credit.)
This is not Beverly Cleary's greatest work, but it's decent. It's a very quick read. A lot of Cleary's books follow a single character on multiple semi-independent misadventures, and this feels more like it could belong as a single thread in such a book.
Additionally, most have more friends/supporting characters -- Maggie seems basically friendless, and there are no characters of real note, in my view. The characters with multiple scenes are Maggie, her parents, her teacher, the principal, and that annoying boy whose entire role is to repeatedly shove the school table into her stomach (and I guess the other girl at that table? I forget her name.) -- basically nothing but adults, who don't really count as real people when you're viewing the world from the perspective of an eight year old.
In addition to the title nickname, one other thing that feels under-developed is how Maggie observes various adults writing improper cursive -- her dad doesn't "close his loops", and her left-handed mother's slants the wrong way. She intentionally writes this way a few times when told to practice, and when challenged simply responses "I'm writing like a grown-up." But then...nothing. No one inquires as to what that means, and it's never resolved in her own mind. (She does, after "learning" cursive, inform her parents that they should correct their writing.) This is one thing I recognized when I re-read it after thirty years, so it's significant, but just unused.
My mom read this book to me when I was pretty young -- presumably age 7-9, as that's how old I was when it came out. I clearly remembered Maggie's annoyance when the teacher got credit for teaching her cursive when Maggie was the one who did all the work. That one thing stuck with me for thirty years, and that's about it.
If you want some silly laughs, go for Ramona. If you want something more chill, maybe go for Ellen Tibbits. But once you've worked your way through those, Henry Huggins, and Mitch and Amy, this is worth having next on your list. I like it. I'd give it 3.5/5 stars on Goodreads if they did half-stars, but they don't, so just 3. Worth reading, but nothing special.
Also, if you have an eight year old kid who's having trouble with cursive...don't count on this book to solve that problem. I still can't even sign my name properly.
* Actually, she learns to read cursive and they decide that if she can read it, she can write it. As a non-cursive-writing adult who can mostly read it, I can assure you this is an entirely unjustified belief.