In what scenarios should session_start() be called in PHP to ensure proper session management across multiple form submissions?

To ensure proper session management across multiple form submissions in PHP, session_start() should be called at the beginning of each script that needs to access or manipulate session data. This function initializes a session or resumes the current one, allowing the script to work with session variables. By calling session_start() at the start of each script, you can ensure that session data is properly maintained and accessible throughout the user's interaction with your application.

<?php
session_start();

// Your PHP code here
?>