I've used Confluence and various wikis for documentation. Lately I'm really enjoying using github markdown with gitlab and running a local gollum server on my laptop. Clicking 'save' commits the page to the local repo with my comment as the commit message. Then when I'm online, I can pull and push. It lets me edit wikis offline, which is a big win in my book.
A Mastodon instance for info/cyber security-minded people.