Note You can create and manage user accounts, if you chose the From the Internet option for your authentication type (if ...

Note   You can create and manage user accounts, if you chose the From the Internet option for your authentication type (if you are using forms-based authentication). If you chose the From a local network option as your authentication type (if you using integrated Windows authentication), you cannot manage individual user accounts. If you change the authentication type, any user information that you have created will be lost. Additionally, access rules might no longer work in the way that you configured them. Generally, you should select an authentication type only when you first configure the Web site.