In this example, the session starts and the form is displayed with the token as a hidden input field. When the user submits the form, the token is sent along with the form data. In the receiving script (`submit.php`), the token is compared with the one stored in the session. If they match, the form data is processed. If not, an error message is displayed. Package library: This feature is available in the core PHP library and does not require any additional packages or libraries.