Quick notes for Modules

Hello all, new here to the forums but im trying to figure out a way to add this to my current modules.

I'm not sure what all would go into it, programming this site (module) wide . But has anyone tried adding a quick notes, or a way to highlight a key point we personally find important. That way, looking back on a topic we have already covered is easier to find?

P.S. I haven't searched an answer for this yet, but it just came to me concluding a very in depth tuning module.