Organic Contact submissions vs PPC

Hi All,

I am trying to figure out a way to include in a contact form submission if the visitor found the website organically or through PPC. The website I’m recreating used this code previously:

<?php

$name = $_POST["name"];
$phone = $_POST["phone"];
$email = $_POST["email"];
$message = $_POST["message"];
$formType = $_POST["form-type"];

//handle check boxes

$interest = null;

$pavers = isset($_POST["pavers"]);
$design = isset($_POST["design"]);
$water = isset($_POST["water"]);
$turf = isset($_POST["turf"]);

if($pavers){
	$interest .= "Pavers [x] ";
}
if($design){
	$interest .= "Design [x] ";
}
if($water){
	$interest .= "Water Feature [x] ";
}
if($turf){
	$interest .= "Turf [x] ";
}

$headers = 'From:  (Email address hidden if logged out) ';

$seoData = null;

if(isset($_COOKIE['PPC'])){
	$seoData = "PPC";
}else{
	$seoData = "Organic";
}

if ($formType == "long"){
	$estimateForm = "Estimate Form:\rName: $name\rPhone: $phone\rEmail: $email\rEstimate for:\r$interest\rMessage: $message\rSEO Data: $seoData";
	$subject = "PPI Estimate Form";
}else{
	$estimateForm = "Short Form:\r Name: $name\rPhone: $phone\r SEO Data: $seoData";
	$subject = "PPI Short Form";
}

			$to = join(', ', array(
				' (Email address hidden if logged out) ',
				' (Email address hidden if logged out) ',
				' (Email address hidden if logged out) ',
			));

		mail($to, $subject, $estimateForm, $headers);

?>

I don’t know how to read php, so I’m not sure if that helps.

Thanks for your help!