<?php
$name = $_POST['name'];
$to = "alexalphapol@gmail.com";
$subject = "Заявка с сайта" ;
$name = trim(htmlspecialchars($name));
$message = "";
$headers = 'From: alexpol alexalphapol@gmail.com' . "\r\n" .
    'Reply-To: alexalphapol@gmail.com' . "\r\n" .
    'X-Mailer: PHP/' . phpversion();

mail ($to, $subject, $message, $headers);
$extra = 'index.php';
header("Location: /$extra");
exit;
?>