thank_you.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Test Form</title>

<link rel="stylesheet" href="css/bootstrapv4.css" />
<link rel="stylesheet" href="css/styles.css" />
<link href="https://fonts.googleapis.com/css?family=Quicksand" rel="stylesheet">
</head>

<body>

  <div class="container">
     <div class="row">
         <div class="col-lg-12" align="center">
            <h1>Thank you</h1>
         </div>
     </div>
  </div>
  

<script src="js/jquery.min.js"></script>
<script src="js/index.js"></script>

</body>
</html>