If you registered your Fauna account using GitHub or Netlify, you can opt into email+password authentication by completing the Forgot Password workflow. Your account email is the email linked to your 3rd-party account at the time you registered with Fauna. Github and Netlify do not push changes to Fauna.
If you wish to unlink your account from Github or Netlify, then please open a support ticket using your account email. Once your account is unlinked, you can set a new password using the Forgot Password workflow.
You can view your account email under Personal Settings page in the dashboard.