Check out Attribute on WooCommerce

As it happens, I just blogged about this yesterday, for how to add a subscribe to mailing list checkbox. The key points are:

• look at the WooCommerce tutorial
• woocommerce_checkout_fields is a filter hook that allows you to add or modify what fields appear on the checkout form
• woocommerce_checkout_update_order_meta is an action hook that allows you to save your new fields
• woocommerce_email_order_meta_keys is a filter hook that allows you to add your new fields to the confirmation emails
• the name you pick to save the post meta will be its label in the email

Here’s the code I used:

class WooSubscribeCheckbox {

    // add hooks into WooCommerce
    public static function run() {
        add_filter('woocommerce_checkout_fields',
            array(__CLASS__, 'filterWooCheckoutFields'));

        add_action('woocommerce_checkout_update_order_meta',
            array(__CLASS__, 'actionWooCheckoutUpdateOrderMeta'));

        add_filter('woocommerce_email_order_meta_keys',
            array(__CLASS__, 'filterWooEmailOrderMetaKeys'));
    }

    /**
    * add custom fields to WooCommerce checkout
    * @param array fields
    * @return array
    */
    public static function filterWooCheckoutFields($fields) {
        global $woocommerce;

        // add field at end of billing fields section
        $fields['billing']['our_mailing_subscribe'] = array(
            'type' => 'checkbox',
            'label' => 'Subscribe to mailing list?',
            'placeholder' => 'Subscribe to mailing list',
            'required' => false,
            'class' => array(),
            'label_class' => array(),
        );

        return $fields;
    }

    /**
    * save custom order fields
    * @param int $order_id
    */
    public static function actionWooCheckoutUpdateOrderMeta($order_id) {
        if (isset($_POST['our_mailing_subscribe'])) {
            update_post_meta($order_id, 'Subscribe to mailing list',
                stripslashes($_POST['our_mailing_subscribe']));
        }
    }

    /**
    * add our custom fields to WooCommerce order emails
    * @param array $keys
    * @return array
    */
    public static function filterWooEmailOrderMetaKeys($keys) {
        $keys[] = 'Subscribe to mailing list';

        return $keys;
    }

}

WooSubscribeCheckbox::run();