How to I send messages in PHP

<?php 

include 'index.php';



$name =  $_POST["name"];
$email =  $_POST["email"];
$number =  $_POST["number"];
$Message = $_POST["Message"];



$to = "sean971@gmail.com";

//sender - from the form
$from = $name . ' <' . $email . '>';
//subject and the html message
$subject = 'Message from ' . $name;
$message = 'Name: ' . $name . '<br/><br/>
      Email: ' . $email . '<br/><br/>
  Phone: ' . $number . '<br/><br/>
      Message: ' . nl2br($Message) . '<br/>';

$result = mail($to, $subject, $message, $from);

if ($result)  {  
          echo "<script> $('#thanksModal').modal('show')</script>";

 } else if (!$result){

     echo 'Sorry, unexpected error. Please try again later';

} 






?>