I think you’re correct about figuring out how the different account creation methods should be reflected in the docs.
For the end-user Getting Started docs though, I think this should suffice. Think of how an end user, who knows nothing about the inner workings of Mattermost, experiences creating an account and signing up for the first time. Because the experience is fairly consistent with other online software systems, they can use their previous experience with those other systems plus the Mattermost sign-in UI to figure out what to do, with no need to look at the documentation. The primary reason for an end user to come here is if for some reason they’re having trouble, so that’s one of the people who this page is designed for.
Also, we need to consider who else is in the audience, and that’s people who don’t yet use Mattermost and are looking to see how it works before going to the trouble of downloading and installing. Slack is easy; sign up and you’re done. But if I’m considering Mattermost for my organization, I want to know if it’s worth the extra trouble. Yes, I get to own my data, but at what cost? Is it one of those cheap free software thingys with half the features, some of which actually work? Or is it a highly capable realistic alternative to other chat systems? The docs should confirm and amplify the truth: Mattermost is great software and is the best choice.
Also for the prospective buyer, this page tells them some things that they might not get from the main Mattermost web site. It says that the onboarding process is highly configurable, that the password has configurable restrictions, that there’s a built-in tutorial experience for users when they sign in the first time, that users have profiles that they can modify, and that only 3 pieces of info are required during sign-up.
More is needed for administration section though. As an administrator, how do I onboard my 100 or so users? What if I have 2000 users? How do I know what to put in those emails? Do I have to create 2000 emails, or will Mattermost do that for me? Is there a better way? The info is spread throughout the docs, but it’s not easy to find; you pretty much have to read them from start to finish before finding out how to do this. Much more work is needed.