How can I delete a customer from my customer list?

I'll walk you through deleting a customer in QuickBooks Online (QBO), @gert1. This way, they'll be removed from your customer list. 

Let's go to the Customers tab to achieve your goal. Please take note that the transactions associated with a deleted customer will remain in reports. It's because we want to ensure your books are still intact and accurate in QBO. I'll guide you how. 

1. Go to Sales from the left menu. 
2. Select Customers.
3. Click the customer’s name.
4. Hit Edit. 
5. Choose Make inactive.
6. Click Yes to confirm the deletion. 

The screenshot below shows you the last three steps. For your reference, see this article's Delete a customer section: Managing Customer List. This link also contains steps on how to add sub-customers and merge duplicate customers. 

In case you need to make that customer active again, I'd suggest reactivating them. Just go back to the Customers tab to complete this task. For the detailed instructions, visit this article: Reactivate A Customer. 

I'll be right here to help if you need further assistance. Wishing you and your business continued success, @gert1.