How is credential transmission carried out when using basic authentication?

In Basic Authentication, credentials (username and password) are transmitted in the HTTP header Authorization. The username and password are combined into a string in the format username:password, then this string is Base64 encoded. A prefix Basic is added to the encoded string and included in the header. For example:

Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ=

The server decodes this header, extracts the username and password, and verifies them for user authentication. This method does not encrypt data, so it is recommended to use it only over a secure HTTPS connection.