You could do a lot worse than read about the concept of a Zettelkasten or Commonplace book. Here's my notes on the two. I am currently using the app Bear to take notes on everything and anything, tagging as I go, and trying my best to link notes to other meaningful notes. Less formal than a Zettelkasten but more digital than your average commonplace book.
A different concept, but also with relevance to storing information for a lifetime. From my brief readings, there’s more emphasis placed on two stages of note. The first is a quick jot - an addition. The second is a more thought out, self-contained existence of the note. There’s also focus placed here on _linking_ notes together.