@EllenInEdmonton @Giselle
Yes, those apps are similar to #Joplin (as I understand it) but Joplin is no-charge and has an amazingly small footprint for a lot of content (mine).
I think I first tried this sort of thing with Agenda and woth a handful of notes it ballooned to a huge size for storage. On Joplin, I had literally thousands of notes in it before it got anywhere near the size of Agenda on my iOS device.
I've also loved how I can organise it entirely however I want, with both Markdown and HTML functionality, as well as internal cross-linking. It also has tags but I use a different system of my own that works better for me (and that I developed long before for use on other files I keep, so things remain consistent.)
For me, it's like a personal, private website full of data I actually want and use, and no ads either. 
Folks all have their organising preferences but my own recommendation to consider remains #Joplin.