Thank you for reaching back to us, @jeasalva. 

Currently, adding more than one date under the Service Date column is unavailable in QuickBooks. You can add dates one at a time. As an option, you can use the Description field to indicate the information. 

For additional reference, you can check this article on how to customize invoices, estimates, and sales receipts. 

To understand more about reports, please check out this article for your future reference: Understand Reports. 

This should get you on the right track. Feel free to leave a comment below if you have questions about customizing the report. I'm always here to help.