I want to add these headers to whole wordpress site without including it in each file/plugin.

I know what Wordpress use PHPMailer for email sending. But I don't know how to add headers to outgoing emails.

For example I need to add these headers to all outgoing emails.

$headers = "From: " .($from) . "\r\n";
$headers .= "Reply-To: ".($from) . "\r\n";
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-Type: text/html; charset=ISO-8859-1\r\n";
$headers .= "X-Priority: 3\r\n";
$headers .= "X-Mailer: PHP". phpversion() ."\r\n";

What I need to add into this hook ?

add_action( 'phpmailer_init', function( $m ) {
    //CODE HERE
} );

Thanks in advance