Thanks for coming back for more support. @chiaracammarata. I understand the need to have the ability to show milestones that were billed against it so you can see where the project stands in the Project Overview or Budget vs. Actual reports.
For now, we're unable to create one report with that information. In the meantime, you'll want to pull up Estimates & Progress Invoicing Summary by Customer report. This will show the pending and closed estimates per customer as well as if it's been invoiced.
For future reference, I've included these articles to learn more about how to use the project feature in QuickBooks Online:
Let me know if you have additional questions. We're always here to be of your service.
