HI @yett
I think you would need to add the field to the order not the product.
You then need to add the code to the emails:
/**
* Add a custom field (in an order) to the emails
*/
add_filter( 'woocommerce_email_order_meta_fields', 'custom_woocommerce_email_order_meta_fields', 10, 3 );
function custom_woocommerce_email_order_meta_fields( $fields, $sent_to_admin, $order ) {
$fields['Begindatum'] = array(
'label' => __( 'Begin Datum' ),
'value' => get_post_meta( $order->id, 'Begindatum', true ),
);
return $fields;
}
If you’re using a plugin for the invoices, you may need to check if they have any hooks
