Some kind of screen sharing app with Krita = virtual whiteboard. You have a lot more room than a real whiteboard offers, since Krita has a "pseudo-infinite" can

Some kind of screen sharing app with Krita = virtual whiteboard. You have a lot more room than a real whiteboard offers, since Krita has a "pseudo-infinite" canvas, so you don't need to erase things. And you can save the file for reference, or to send it other people.