The Notes app is one of my favorites. Lightweight and synced across all of my devices.
I use it for creating the content for my Instagram post captions.
I usually type them up on my laptop or iPad and then copy that content into my Instagram post.
While the app is missing a lot of features that more robust solutions have, it works for me. It doesn’t have any features I do not need.
The other reason I really like the Notes app is that when I am using my iPad Pro, I can pick up the pencil and sketch out some ideas. The ability to do this makes the iPad feel a little bit more like a notebook.