OAuth tokens are digital keys used in the OAuth authentication framework, allowing users to grant third-party applications access to their data without sharing their passwords. When a user logs in to an app using OAuth, they receive a token that represents their permission for the app to access specific information. These tokens come in two main types: access tokens and refresh tokens. An access token allows the app to access the user's data for a limited time, while a refresh token can be used to obtain a new access token when the original expires, ensuring continuous access without requiring the user to log in again.