Hi harrowpt,
Welcome to Community! Having the option to make customers inactive is a great way to keep your books clean. QuickBooks Online has the features you need when changes are necessary in your customer list. I'll be happy to assist!
When you make a customer inactive, they'll be hidden from the list. Here's how to make a customer active;
1. From the left menu, open Sales and then Customers
2. Select the small ⚙ icon above the Action column and then choose Include inactive
3. Locate the customer name in the list and hit Make active, in the Action column
You're all set!
Here's a helpful guide to assist with managing customers in QuickBooks Online.
Let us know if this has been solved. If you have other questions, please feel free to reach back out. We'd love to help!