Send emails from html form

<?php
// this code must be on some.php file on hosting. You can not use this code on localhost PC!
// change webmaster@example.com in what you want!

  if (isset($_REQUEST['to']))  {

  //Email information
  $to= $_REQUEST['to'];
  $from = $_REQUEST['from'];
  $subject = $_REQUEST['subject'];
  $message = $_REQUEST['message'];

$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/html;charset=UTF-8" . "\r\n";
$headers .= 'From: <webmaster@example.com>' . "\r\n";


  //send email
  mail($to, $subject, $message, $headers);

  //Email response
  echo "Thank you for sending email!";
  }

  //if "email" variable is not filled out, display the form
  else  {
?>

 <form method="post">
  From: webmaster@example.com <br />
  To: <input name="to" type="text" /><br />
  Subject: <input name="subject" type="text" /><br />
  Message:<br />
  <textarea name="message" rows="15" cols="40"></textarea><br />
  <input type="submit" value="Submit" />
  </form>

<?php
  }
?>