How do I add an auto reply function to this PHP script? [duplicate]

I managed to get the form to send me mail but would like to auto respond with a thank you message.

<?php

if (isset($_POST['submit'])) {
  $name = $_POST['name'];
  $subject = "Email Confirmation";
  $mailFrom = $_POST['email'];

  $mailTo = "info@nulla.com";
  $headers = "From: ".$mailFrom;
  $txt = $name." Just Signed Up to Nulla!";

  mail($mailTo, $subject, $txt, $headers);
  header("Location: http://nulla.com/#subForm");
}