OAuth 2.0 is an authorization framework that allows third-party applications to access a user's data without sharing their password. It enables users to grant limited access to their information on one service to another service, using tokens instead of credentials. This enhances security by minimizing the risk of password exposure. The process involves several roles: the resource owner (user), the client (third-party application), the authorization server (which issues tokens), and the resource server (which holds the user's data). By using OAuth 2.0, users can control what information they share and revoke access at any time.