Hi there toni-oasislavend,
It's important that all your transactions are entered correctly for your books to be well balanced. QuickBooks Online is a great tool able to help you keep track of sales and expenses so you can see the profit of your business. I can point you in the right direction to view information about products and invoices.
To see all transactions related to a product, including invoices, you can go to the Sales tab, then Products and Services. Find the product in question, then click on the drop-down arrow in the Action column of the row to Run report. This will show you a list of transactions with the product in question, you'll just need to select the date range wanted for the report.
If you have any other questions, feel free to reach out here.
