<?php
$to      = 'user@site.ru';
$subject = 'test subject';
$message = 'hello';
$headers =  'From: no-reply@site.ru' . "\r\n" .
    'Reply-To: no-reply@site.ru' . "\r\n" .
    'X-Mailer: PHP/' . phpversion();


$r = mail($to, $subject, $message, $headers);
var_dump($r);


?>