Hello, farrellpe. 

In QuickBooks, a simple way to make sure you don’t enter duplicate customers or job is to have a simple naming standard that you use whenever you enter new customers. You can follow QBteach suggestions to manage the customers. To modify the job name or the customer name. Here's how:  

1. Click the Customers and choose Customer Center.
2. Under Customers & Jobs. Select the Customer's name to open their information.
3. Edit the name and hit OK.

For more details, please see this article: Change vendor, customer or employee name type. 

I've also added this how to track job costs in QuickBooks Desktop for your reference.

Reach out to me if you have clarification. I'm more than happy to explain further. Take care and have a good day!