WooCommerce manages information on product Availability (aka Stock), Prices, SKU, etc., but additional WooCommerce product attributes must be created to provide more product information for Google.
The WPSSO Core Pro plugin (and its WPSSO Schema JSON-LD Markup Pro add-on), for example, include a variety of WooCommerce product attribute values in its Schema markup, including the product Brand, Color, Condition, EAN, GTIN-8, GTIN-12, GTIN-13, GTIN-14, ISBN, Material, MPN (aka Manufacturer Part Number), Size, and Gender.
Google’s Testing Tool Reports a “missing global identifier”?
If the Google Testing Tool reports a “missing global identifier” error for your WooCommerce products, please note that the missing global identifier referred to by Google is not the Schema ‘productID’ property, but a general term used by Google for a missing globally common product identifier like the ‘mpn’ property (aka Manufacturer Part Number) or another globally common product identifier (ISBN, GTIN, etc.).
Unfortunately, the often used product ‘sku’ property (aka Stock Keeping Unit) is a value that changes from one retailer to another, so is not valid as a globally common product identifier.
If the Google Testing Tool reports a “missing global identifier” error for your Schema Product markup (and assuming you are using the WPSSO Core Pro plugin and its WPSSO JSON Pro add-on), make sure you have created one or more WooCommerce attributes for the product MPN, ISBN, GTIN, etc., and update these values for all your products.
Better Schema for WooCommerce
See the Better Schema for WooCommerce Step-by-step Guide for additional information on solving common Google Testing Tool warnings for WooCommere products.