[deepakg]

For short notes I've been using deft[1] on emacs. It gives a Notational Velocity like interface for searching/viewing within emacs. The actual note-taking is via org-mode.

For notes from online courses, I recently started using the stock Notes app on macOS/iOS because of the Pencil support on the iPad.

Not sure if this helps as I don't know what platform/editor you use and I wouldn't expect you to switch either for note taking :)

1. https://jblevins.org/projects/deft/