It's important to me that I can take notes on my phone because it's the thing I have on me most of the time (unlike a laptop or notebook). Sometimes a random thought pops up and will distract me until I write it down. On my laptop I can use the Signal desktop app to view, add, or search notes. Every note automatically gets a timestamp and is synced between my devices. Both taking and viewing notes works without an Internet connection.
Notes can't be edited but more information can be added by replying to a note and the new information gets its own timestamp. Sometimes I also use emoji reactions as tags. Recently I've started to use groups in which I'm the only member as note categories (e.g. ideas, thoughts, journal, work).