Authorizing with a user's username and password using OpenIddict. The full name of this flow is Resource Owner Password Credentials, though you'll also see it called the Password Flow.
OpenIddict is an open source project for building an authorization server. It focuses only on authorization, so whatever you use to authenticate your users can work alongside OpenIddict.
OData is the standard protocol that allows access to the RESTful APIs in the sample and standard way. The benefit of OData is providing create, read, update, and delete operations via web technologies to provide access to information from API.