It is a protocol that describes how servers and services can allow access to resources without sharing the logon credentials .
A user is sending a picture over email and as they attach the photo in your cloud the OAuth is seemlessly authinticating the logon to your cloud so that you can select it to the email service.
OpenID is a standard decentralized authentication protocol that allows user to login to multiple applications. Its liek a digitial identitity badge
authentication is verification of identity where authorization actually gives you access.
Authorization Code Flow us ab exachnging an authorization code for a token
Its an authentication and authorization flow designed to enhance security. the PKCE aspect is esentially an extra step where before creating the token request, the client generates a random string and computes its value.
Its a form of authorization code flow for sites or applications which cannot scurely store client info
it is a flow for Machine to machine applications
Authentication where the user is given a ling they can click to authorize their device.
A flow where the password and user name are sent to the backend to be stored (Not Recommended)