add user meta to order meta

Hi,

Do you know the way how to add a custom user field to the order as meta data?
I tried some things but I am getting errors all the time:

// Add the user meta as order meta data
add_action( 'woocommerce_order_status_wordt-verwerkt', 'add_wefactemail_to_order_meta_data', 10, 2 );
function add_wefactemail_to_order_meta_data( $order ) {
  $user_id = $order->get_user_id(); // Get the user id
  $wefactemail = get_user_meta( $user_id, 'KVK_nummer_2', true );
  $order->update_meta_data( 'WeFact_Billing_Email', $wefactemail );
}

Also, I am using the custom order status plugin from WooCommerce. So I am trying to add the action when we are updating the order status to the custom order status “wordt-verwerkt”.

I hope you can help me out.

Best,
Olga