Thanks for getting back to us, @nessllc1.
Are you referring to the Accounts Receivable (A/R) Aging Summary report? If so, as mentioned above, the default sorting option is in alphabetical order. This only applies to parent customers.
Below is a sample screenshot from my QuickBooks Desktop (QBDT) sample file.
On the other hand, if you're referring to the sub-customers or jobs, QBDT doesn't have an option to sort them alphabetically. You can export them to Excel and customize it from there as a workaround. Here's how:
1. Click the Excel drop-down at the top.
2. Pick Create New Worksheet.
3. Select Export.
Just in case, I'm also adding these articles for future reference:
Please let me know if you have any additional questions or concerns. I'm always here for further assistance. Have a great day!