What are the differences between using 'mail' and 'sendmail' as the factory method in PHP's Mail package for sending emails?

When using PHP's Mail package to send emails, the main difference between using 'mail' and 'sendmail' as the factory method is the underlying method used to send the email. 'mail' uses the built-in PHP mail() function to send emails, while 'sendmail' uses the sendmail program installed on the server. Using 'sendmail' can provide more control and flexibility over the email sending process, but may require additional configuration.

// Using 'mail' as the factory method
$mail = new Mail();
$mail->factory('mail');

// Using 'sendmail' as the factory method
$mail = new Mail();
$mail->factory('sendmail');