Let me tell you about
It’s free, available on Mac or PC, has an app for your phone and is fucking amazing.
It’s all the fun of an old school binder, including tabs, sub pages and images, entirely in a digital easy to edit space.
It’s great for people who want to keep large campaign binders but ink is expensive yo, and this is available to edit and make changes at any point throughout your day.
I’ve got an example here of my section for the world map of my campaign setting, and the individual pages for the individual locations.
Then I’ve got the faction page I made with each faction’s individual page and symbol.
Then you’re shown a look at a individual faction page as an example.
You can also password protect sections you don’t want anyone besides yourself, the DM, to have access to meaning you’re free to share this binder freely with your players.
Your players can have your entire campaign setting, where they’ve been, the npcs, the factions, etc. available at their finger times that updates in real time.
It can sync between all your devices too.
I can not recommend one note any more highly for D&D prep and planning. It is seriously a life saver.