How are customer sub-accounts created in QuickBooks Online?

Hi there, @jackn1. I can help you with set up your customer sub-accounts in QuickBooks Online. 

Sub-accounts or sub-customers is essential when you want to track your individual buyer who is part of a group or an organization. Although you can have an unlimited number of sub-customers, please note that a single parent account is limited to accommodating up to four accounts. To create one, please follow the steps below: 

1. Open your QuickBooks account and ensure you've already set up your parent account. 
2. Head to Sales, then Customers. 
3. Click the New customer button and enter your sub-accounts information on the Customer window.
4. Once done, tick the Is a sub-customer checkbox under Name and contact section. 
5. Select the Parent customer from the dropdown. 
6. Check the Bill parent customer box if you wish to invoice the sub-customer along with the parent customer. If you prefer to bill the sub-customer individually, leave this box unchecked.
7. Add the remaining information needed, then Save. 

For additional information and reference, please see this article: Add and manage customers in QuickBooks Online.

I'll include this article you can read if you want to get an overview of your business data and track your financial reports in QuickBooks: Run a report in QuickBooks Online.

You can always visit this forum if you have other concerns about creating sub-customers in QuickBooks, @jackn1. We'll be here to help you anytime.