Hey there, @donnagrail,
Thanks for adding to the conversation. Allow me to share some information about linking a purchase order to your estimates.
These transactions are non-posting, thus linking them is currently unavailable feature in QuickBooks Desktop. The only way you can complete your task is to export your report to Excel then manually update the data you need from there.
I understand how handy this feature can help your organization. While the preference you're looking for is currently not an option in QuickBooks, rest assured that I'm making it my top priority that your suggestion reaches our developers.
That should do it. Please let me know if you have any questions with QuickBooks Desktop. I'll be more than happy to answer them for you. Have a nice day!