Hi martinmorelmecha,
Welcome to Community! QuickBooks Online provides a wide range of reports, so you can view specific areas of your books. I would be glad to provide some insight here!
If you've set up your labour costs as a service, to be added to your invoices, I recommend taking a look at the Sales by Product/Service Detail report. You'll want to select the Report period, then open the Customize option. In this area, you'll be able to Group by product/service and select specific filters. When you hit Run report, your items will be grouped accordingly, with the totals for each product/service.
Feel free to reach out again, if you have other questions. We would be happy to help!