The Authorization Code Flow is one of the OAuth2 flows that was designed to securely authenticate a user and issue an access token. The basic concept behind the authorization code flow is that a code is issued after identification and this must be exchanged for an access token.
Benefits
The Authorization Code Flow with PKCE (Proof Key for Code Exchange) is an extension of the Authorization Code Flow. It is specifically designed to authenticate native or mobile application users, but is recommended for all scenarios where user authentication is required, especially for public clients that cannot securely store a client_secret.