Welcome and thank you for joining this Community thread, product id. I see you're looking for an easy way to get the product/item Id for your API resource reference. Allow me to share some details and make sure you'll routed to the forum for this concern.

While you can view and manage products, services, and inventory items within the interface, the item Id are not explicitly displayed or easily accessible. Keep in mind that the interface in QuickBooks Online is designed for user-friendly accounting and bookkeeping. This means, direct access to underlying data such product/item Id for API resource is unavailable. 

You can visit our dedicated forum for Intuit Developers so you can ask further information on how you can obtain API data such as product/item Id.

I've also added this articles for more information: What you can do with the QuickBooks Online Accounting API.

If you have any further concerns or questions about QuickBooks Online or its products and services, feel free to leave them in the comments. I'd be happy to help.