title: Where are users stored when using v2.0 common endpoint
body: <p>If I register an app in <a href="https://apps.dev.microsoft.com/" rel="nofollow noreferrer">https://apps.dev.microsoft.com/</a> it works as intended. I can modify the endpoint to use a specific AD tenant, or to just use "common" <em>(Allows users with both personal Microsoft accounts and work/school accounts from Azure Active Directory to sign into the application.)</em></p>
  
  <p>My question is, when using common, i.e <code>https://login.microsoftonline.com/common/oauth2/v2.0/...</code></p>
  
  <p>Where do new users get stored? I want people to be able to sign in/create accounts using any Microsoft account (common), but where are they stored when I use this endpoint? How do I administer them and/or my application as I would a normal AAD Tenant with an application registration?</p>