Add a custom field to an order in WooCommerce 3+ - php

Question

In WooCommerce, I would like to add a new custom field to order details. I now that I can use use the code below to create a new custom field 'referenceNumber' and adds in it "ordercreated" value:
update_post_meta($order_id, 'referenceNumber', 'ordercreated']);
What I would like is to make that through checkout once an order is placed.
But it doesn't work it doesn't add a new custom field to order details page and don't add the value 'ordercreated', as you can see in this screenshot:
So the question is how to add a custom field when an order is placed in WooCommerce?

Answer 1

To add a custom field to an order you can use:
WordPress update_post_meta() function (from an order id):
$order_id = $order->get_id(); // If needed
update_post_meta($order_id, 'referenceNumber', 'ordercreated'); // add and save the custom field
WooCommerce WC_Data update_meta_data() method (from the order object or the order id):
$order = wc_get_order( $order_id ); // If needed: Get the WC_Order object from the order Id
update_meta_data('referenceNumber', 'ordercreated'); // Add the custom field
$order->save(); // Save the data
Where referenceNumber is the meta key and ordercreated is the meta value. Both works.
Now to add a custom field to an order when customer place an order, you can use:
woocommerce_checkout_create_order action hook (before order data is saved - used to adjust order data before it's saved):
add_action( 'woocommerce_checkout_create_order', 'add_custom_field_on_placed_order', 10, 2 );
function add_custom_field_on_placed_order( $order, $data ){
$order->update_meta_data( 'referenceNumber', 'ordercreated' );
}
woocommerce_checkout_update_order_meta action hook (order already exist - used to add custom meta data):
add_action( 'woocommerce_checkout_create_order', 'add_custom_field_on_placed_order', 10, 2 );
function add_custom_field_on_placed_order( $order_id, $data ){
$order->update_meta_data( 'referenceNumber', 'ordercreated' );
}
woocommerce_checkout_order_created action hook (order already exist - to trigger an action or also to add custom meta data):
add_action( 'woocommerce_checkout_order_created', 'add_custom_field_on_placed_order', 10, 2 );
function add_custom_field_on_placed_order( $order_id, $data ){
$order->update_meta_data( 'referenceNumber', 'ordercreated' ); // Add the custom field
$order->save(); // Save data (as order exist yet)
}
Or:
add_action( 'woocommerce_checkout_order_created', 'add_custom_field_on_placed_order' );
function add_custom_field_on_placed_order( $order ){
update_post_meta($order->get_id(), 'referenceNumber', 'ordercreated');
}
Code goes in functions.php file of your active child theme (or active theme). Tested and works.

Answer 2

Hi i had a similar requirement few days ago, as i needed to add new field at checkout. Following article helped me. You can check it too. Here is the link. Basically you will have a write a function which will use woo commerce hook "woocommerce_default_address_fields"
https://wisdmlabs.com/blog/add-custom-fields-woocommerce-checkout-page/