# Additional Headers

Arbitrary mail headers can be set by using the `addHeader()` method. It requires two parameters containing the name and the value of the header field. A third optional parameter determines if the header should have only one or multiple values:

## Adding E-Mail Message Headers

    $mail = new Zend_Mail();
    $mail->addHeader('X-MailGenerator', 'MyCoolApplication');
    $mail->addHeader('X-greetingsTo', 'Mom', true); // multiple values
    $mail->addHeader('X-greetingsTo', 'Dad', true);

To set the Reply-To: header there exists the function `setReplyTo($email, $name=null)`, because it requires additional special escaping of the different parts (email and name).