Help with forms

Hi, i have created several landings pages at WebFlow, but I have some questions about the forms to send at contact forms with a send.php file.

Currently I have a fairly simple code but does not work properly on all hostings, maybe some firewall is blocking. I’m not expert in php.

Implement this code in my landings:

<?php
$name = $_POST['name'];
$phone = $_POST['phone'];
$email = $_POST['email'];
$msg = $_POST['msg'];
$subject = 'Contact Landing';
$from = "From:contact@website.cl";

$message = "Name: " . $name . " \r\n";
$message .= "Phone: " . $phone . " \r\n";
$message .= "E-mail: " . $email . " \r\n";	
$message .= "Send " . date('d/m/Y', time()) . " \r\n";
$message .= "Message: " . $msg . "\r\n";
$message .= " \r\nContact Landing ";
$for = 'contact@website.cl';

mail($for, $subject, utf8_decode($message), $from);    
echo "<script>window.location = 'thanks.html'</script>";

?>

How I can successfully deploy a file/method to send emails the forms designed at WebFlow?
Does the system validation of forms at WebFlow I still work with this method? Because I tried at iphone and messages can be sent with empty fields.

Sorry if I did not explain well, use google translate.

Thanks.