Filter New Order email headers for WooCommerce

reply-to-order-filter.php

add_filter('woocommerce_email_header', 'spigot_reply_to_mail_filter', 11, 3);


function spigot_reply_to_mail_filter($headers = '', $ordertype = 'new_order', $order = '') {

	if(!is_object($order) || empty($order) || $ordertype !== 'new_order') { return $headers; }

	$name = $order->get_billing_first_name().' '.$order->get_billing_last_name();
	$email = $order->get_billing_email();

	if(is_array($headers)) {
		$headers['Reply-To'] = "{$name} <{$email}>";
	} else {
		$headers .= "Reply-To: {$name} <{$email}>\r\n";
	}
	
	return $headers;
}