You can run and customized the Quotes by Customer report. This displays a list of all the quotes you created in QuickBooks. Also, you'd know whether it was send to your customers or not. I can guide you on how to do it.
Go to the Reports menu.
Scroll down to the Sales and Customers section.
Double-click on the Quotes by Customer report.
Click the Customise button.
Set the report's Date Range.
From the Rows/Columns section, click the Change columns link.