Currently, the option to add a Sales Rep column specifically to the Estimates and Progress Invoicing Summary by Customer report is unavailable because the report has a limited selection of available columns.
As a workaround, run the Transaction List by Customer report, click Customize, and under the Columns tab, check the Sales Rep box. This allows the custom column you created to appear on the report.
You can also explore our QuickBooks Live Assisted if you need expert guidance with customizing your reporting tasks.
Please let us know if you have any other questions!