The authorization code flow is available to Clients which allow interaction with a human user. The Client application displays a window with a web browser which sends an HTTP GET to the Identity Provider. When the human user enters credentials that the Identity Provider validates the Identity Provider returns an authorization code which is passed to the Authorization Service. The Authorization Service validates the code and returns an Access Token to the Client.
The complete flow is described in RFC 6749 Clause 4.1.
A requestType of “authorization_code” in the UserTokenPolicy (see 6.5.2) means the Authorization Service supports the authorization code flow.