Hello there, david.
In QuickBooks Self-Employed (QBSE), it's not possible to generate a report for revenue by product. The invoicing feature in QBSE is just for keeping track of your sales.
If you need this kind of feature, QuickBooks Online (QBO) is another option designed for small businesses. If it suits your business needs, you might want to consider switching to it.
If you have additional questions about the feature in QBSE, don't hesitate to post them here in the Community space. Stay safe!