So currently I use OneNote. It's fine and I can use the app on my phone so it's nice and portable.

However, I am reaching the limit of my app, taking some time.to access my note when flicking around.

It's generally organised as Continent=> Settlement/Location => Character / Buildings / Points of Interest. As you can imagine flitting around from page to page can be a bit time consuming as stuff not limited to a single location has its own notebook.

So DMs how do you organise the chaos that is your campaign notes?

I'm still quite chaotic, but I have a roughly working system now. My main note tool is Notion, which has quite a few things in common with OneNote from what I understand.

The general structure on a campaign level looks like this. These are all separate but can be interlinked if necessary:

1. Per Session Notes - Often interlinked with the Timeline. Herein goes the session planning. It's also a hectic notepad for during the session. The notes here then get translated into proper entries later. For PbP, I do not use this category.
2. Overview - General campaign structure business. Lists the big movers and shakers and their plans. Mostly set up at the start and then rarely adjusted. This is mostly needed for when I run a campaign for the first time and need to have the structure in mind at tall times. Often interlinked with Schemes.
3. PCs - Each pc has a quick-reference entry for when I don't want to pull up the character sheet. This mostly includes:
   • noticeable physical traits like a fancy hat or a large tattoo, for referral by npcs
   • languages they speak
   • hotlink to character sheet
4. NPCs - Serves as a list of names, occasionally with more info.
5. Locations - For location specific notes
6. Timeline - For tracking time. In most campaigns every day gets an entry with the important happenings. For one shots and mini campaigns, this is omitted. Also useful for noting upcoming events, such as the completion of a Scheme or things like lunar eclipses and festivals.

The following sections only get occasional use:

1. Quests - I rarely have strictly defined quests, but this still gets occasional use. Interlinked with NPCs that gave the quest or are involved in them.
2. Schemes - Whenever someone, be it npc or pc has a long term plan, this goes in here. It serves as a list of reminders - often interlinked with the Timeline.
3. Plot Fuel - These are your MacGuffins, but can also be an inciting incident that you plan to make happen.
4. Items - These are items that are specifically not MacGuffins but may be important to a PC, such as a fine wine they once picked up, or an heirloom they have.
5. Factions - Occasionally useful for collecting multiple npcs into a list, but it ends up being too much a chore to bother with most times

So, I have the Broad Outline, the World Lore, A Timeline, and Session Notes.

The Outline tells me the scenes, rumors, gossip, possible side quests, fetch quests, and principal NPCs for each of the Adventures within the larger campaign. Since a campaign  like the one I am doing now can have 60 plus adventures, it is a pretty big outline -- but is basically one of those big books as a whole that is put out. Current Campaign Outline is 380 pages -- but doesn't include any tables or monster stats.

The world Lore is my basic "this is the world" stuff. All the nitty gritty details I need for running the world. It constitutes the infrastructure of the campaign.

THe timeline iis linked to the Outline -- it tells me what happens based only on the actions and issues of the bad guys over time. It also includes gossip, rumors, and news.

Session notes are in two parts: prep and What Happened. I only do the prop part, and a couple of my players do the what happened part (because they like to), but I keep notes that impact the assorted storylines and the main story, a well as tracking time and things relating to the PCs and changes in them.

On sheet per session with a heading for each of the following:

1. NPCs Encountered
2. Quests or tasks Started/Completed
3. Lore Provided
4. Clues Encountered
5. Treasure/Items Acquired
6. Interesting Character interactions & Roleplay moments

Each of these pages form my session notes as a reminder of what happened in each session. I should end up with no more than a single side of A4 paper per session...ever!

For planning a campaign, I start with a list of potential milestones. In a current campaign the outline is that the Riiarians are a people who are seeking to remove magic and magiclike abilities from the world by killing the gods. To do this they need to find and conduct a ritual with an avatar of each god. The party start off by being sent into the world to gather allies and end the threat of the ruler of the Riiarians, eventually defeating her. The broad strokes are as follows:

• Caravine's Avatar is under the protection of the fey, it can regrow the world tree if planted in soil.
  • The Riiarians have sent a poisoner to kill the roots of the world tree and thus force others to bring Caravine's avatar into the material plane where the Riiarians stand a chance of getting their hands on it.
• Provuntul's Avatar has turned up in a town called Gefiell. It was a curio owned by the formed Lord of the town and is now an object that both children of said lord wish to possess as they believe themselves the rightful hier and owner of both Gefiell and the property of their father.
  • The Riiarians will simply attack Gefiell if enough in game time passes.
• Chenical's Avatar exists on the Angry Isle, where an volcano errupted after gnomish tinkering with it. The entire Island is covered by wild magics and the forge where the gnomes were tinkering is now buried.
  • The Gnomes of the Anrgy Isle are attempting to excavate the forge.
• Aocdur's Avatar exists within a meteor that fell to the world.
  • The Riiarians have heard legends and stories and are currently investigating the crash site.
  • The Riiarians will get the avatar first and will begin a ritual on this avatar in the Dead Hills.
  • The ritual requires the sacrifice of 100 lives and will make 1/5th of all spells non-functional.
  • Big Fight to reclaim the avatar
• Wastru's Avatar is in the possession of a Lich who has been attempting to use it to ascend to Godhood.
  • Located in the icy wastes of Ais Abfell
  • Travel is quickest through the conduits (world's version of underdark/deep roads).
• There was another god once - Duine
  • In the sunken plains near the petrified forest a shrine can be found, beneath this shrine is the location where people once successfully completed the ritual and killed duine. As revenge the remaining gods obliterated the land and settlements surrounding the shrine, then caused each sentient creature to develop into either a monstrosity or abberation.
• The Riiarains will offer the party the option to join their side.
  • The ruling council will offer free reign of the fortress and the option to speak with anyone they wish freely.
  • The Riiarians all share the same goal - meritocracy by elminating magic.
  • If siding with Riiarians, the party will be asked to oversee the rituals and recovery of avatars.
• If the avatars are all collected by the party there is an old temple on the Arid Isle...they can be safely stored there...if the party can get to it.
  • If the avatars are locked away in the temple, the gods will decide that all societies and civilisation must be set back to ensure that their existance is never threatened again - by destroying every settlement that exists.
  • The party may choose to fight the scions of the gods that appear and set out on this mission to destroy

Literally that right there is how I plan an entire campaign. That there is the seed. Everything else, and I mean everything else, is derived from this and the actions the players choose. 

For me it breaks down even further though

1. Antagonist(s)
   • Motivation
   • Goal
   • Flaw
2. Potential Allies
   • Individuals
   • Assets
   • Organisations
   • Treasures
3. Critical Mcguffins
   • Items & their location
   • Activities & their component parts
   • Timeline/Timescale

All of this gets contained in a single document either handwritten, or typed out. If I wish to add or build lore that gets done seperately and only as required initially. Everything else is recorded in notes because I like the freedom to alter them as I go.