Enviar correo con PHP

  <form action="envia_mail.php" method="POST" class="code-form form-with-styler" data-form-title="Form Name">

         <div class="dragArea row">

    <div class="col-lg-12 col-md-12 col-sm-12">

    <h2 class="code-section-title mb-0 display-2 text-white">

    <strong>Contactostrong>

    h2>

    div>

    <div class="col-lg-12 col-md-12 col-sm-12">

    <p class="code-text  mb-4 display-7 text-white">Rellena todos los campos para mandar el formulario.

    p>

    div>

    <div data-for="name" class="col-lg-12 col-md col-sm-12 form-group mb-3">

    <input type="text" name="name" placeholder="Nombre" data-form-field="name" class="form-control" value="" >

    div>

    <div class="col-lg-12 col-md col-sm-12 form-group mb-3" data-for="email">

    <input type="email" name="email" placeholder="Correo electrónico" data-form-field="email" class="form-control" value="" >

    div>

    <div class="col-lg-12 col-md col-sm-12 form-group mb-3" data-for="email">

    <textarea name="message" placeholder="Mensaje" data-form-field="textarea" class="form-control" >textarea>

    div>

    <div class="col-md-auto col-12 code-section-btn">

    <button type="submit" class="btn btn-black display-4">Enviarbutton>

    div>

    div>

    form>

 $name = $_POST["name"];

 $email = $_POST["email"];

 $message = $_POST["message"];

 if (!$name AND !$email AND !$message){

   header("Location: contacto.php?msg=off");

   return false;

 }else{

 /*Enviamos el mail*/

   include('lib/template.php');

   include "class.phpmailer.php";

   include "class.smtp.php";

   $email_user = 'tu correo';

   $email_password = 'tu contraseña';

   $the_subject = "Mensaje recibido de tu web";

   $address_to = 'correo para quien va'; 

   $from_name = 'Cursos de programación';

   $phpmailer = new PHPMailer();

   $phpmailer->Username = $email_user;

   $phpmailer->Password = $email_password;

   $phpmailer->SMTPSecure = 'ssl'; 

   $phpmailer->Host = 'SERVIDOR';

   $phpmailer->Port = 465; 

   $phpmailer->isSMTP(); 

   $phpmailer->SMTPAuth = true;

   $phpmailer->setFrom($phpmailer->Username,$from_name);

   $phpmailer->AddAddress($address_to); 

   $phpmailer->FromName = 'Programación Online';  

   $phpmailer->Subject = $the_subject;

   $phpmailer->Body .= $mensaje_correo;

   $phpmailer->IsHTML(true);

   if (!$phpmailer->Send()) {

   header("Location: contacto.php?msg=off");

 }else{

   header("Location: contacto.php?msg=ok");  

 }

 }

 $mensaje_correo = 'contenido';