Sorry but to make the sending mail work, I have to add the send.php file to my site?
Or is there an alternative method?

<section class="section stay-in-touch inverse-color parallax-section" id="anchor07" data-parallax-image="images/demo/stay-in-touch/stay.jpg">
    <div class="container">
      <div class="row">
        <div class="col-xs-12 col-md-6">
          <div class="voffset190"></div>
          <p class="titulo">Stay in<br> Touch</p>
          <div class="voffset20"></div>
          <p class="cousine subtitulo">Subscribe for free downloads and news updates.</p>
          <div class="voffset30"></div>
          <label for="stay-in-touch-email">YOUR EMAIL</label>
          <form action="send.php" method="post">
            <div class="row">
              <div class="col-xs-12 col-sm-8">
                <input name="stay-in-touch-email" id="stay-in-touch-email" type="text" value="">
              </div>
              <div class="col-xs-12 col-sm-4">
                <input name="button" class="btn square stay-in-touch-submit" type="submit" value="GET STARTED">
              </div>
            </div>
          </form>
          <div class="voffset190"></div>
        </div>
      </div>
    </div>
  </section>

<?php
if(!$_POST) exit;
    $to    = '[email protected]'; #Replace your email id...
 $name   = $_POST['txtname'];
 $email    = $_POST['txtemail'];
 $subject  = $_POST['cmbsubject'];
    $comment  = $_POST['txtmessage'];
         if(get_magic_quotes_gpc()) { $comment = stripslashes($comment); }
  $e_subject = 'Messaggio dal sito internet da ' . $name . '.';
  $msg  = "Sei stato contattato dal sito da $name per questa informazione, $subject.\r\n\n";
  $msg .= "$comment\r\n\n";
  $msg .= "Per contattare $name via email, $email.\r\n\n";
  $msg .= "-------------------------------------------------------------------------------------------\r\n";
        
  if(@mail($to, $e_subject, $msg, "From: $email\r\nReturn-Path: $email\r\n"))
  {
   echo "<span class='success-msg'>Grazie per averci contattato, Ti rispoderemo prima possibile.</span>";
  }
  else
  {
   echo "<span class='error-msg'>Sorry your message not sent, Try again Later.</span>";
  }
?>

But it does not work.
What should I do ?
Thank you.