Good morning, @goldcoastwebdesign. 

Thanks for following the thread. 

The purpose of setting customers to inactive is when you no longer need to have the customer on your list. The option to make the customer inactive is a way of removing them. QuickBooks won't allow you to delete the customer if you have any transaction history with them for accounting purposes. Such as invoices, payments, or receipts. 

You can review more details in Add and edit multiple customers, vendors, and items. 

Please let me know if you have further questions or concerns. You can reach out to the Community at any time. Take care!