How can PHP error output be activated and increased to help diagnose issues like class not found errors?

To activate and increase PHP error output to help diagnose issues like class not found errors, you can set the error_reporting level to E_ALL and display_errors to On in your php.ini file or in your PHP script. This will ensure that all errors, including class not found errors, are displayed on the screen.

error_reporting(E_ALL);
ini_set('display_errors', 1);