Comment by morninglight

WordPad was good for this on Windows - maybe too good.

AbiWord looked like it might be similar on Linux, but never kept up.

There is a very light weight, free program called "The Guide" which is also good for notes

https://portableapps.com/apps/office/the_guide_portable

https://theguide.sourceforge.net/

It hasn't been updated for about 8 years, but it doesn't require installation and we have found it very useful.