New in iOS18 (and iPadOS and macOS) are collapsible sections in Notes. This is a nice feature to have in what has always been a bit staid in the note taking department. Notes is really great for taking handwritten notes.
I was wondering when this feature bowed, and I came across these cool guides that Apple publishes. They generally just note new features from device to device, which was helpful for my purposes, but I can see checking them out in the future, too.
I remember when TextEdit had an outlining feature.