我可以在邮件正文中为某些内容设置任何类型的自定义快捷码吗？

eg:

$to = "test@test.com";
$subject = "Test Email";

$packages = do_shortcode(\'[test id="0000"]\');

$message = $packages;

// Always set content-type when sending HTML email
$headers = "MIME-Version: 1.0" . "\\r\\n";
$headers .= "Content-type:text/html;charset=UTF-8" . "\\r\\n";

// More headers
$headers .= \'From: <webmaster@example.com>\' . "\\r\\n";

mail($to,$subject,$message,$headers)