How do you delete sub-accounts that are no longer needed?

Thanks for visiting the Intuit Community, treasurer. I'd be glad to share information about deleting sub-accounts in QuickBooks Online (QBO).

In QuickBooks Online, there's no option to delete the sub-account completely. However, you can make it inactive instead of deleting it so you can have access to the past transaction data.

Additionally, if you make an account  inactive with a balance, QuickBooks creates a journal entry and moves the remaining balance to another account. But if your account has 0 balance, you can easily make it inactive. Allow me to walk you through the process:

1. Click the Gear icon.
2. Under the Your Company, click Chart of accounts.
3. Look for the account that you want to delete.
4. Select the Action drop-down and select Make inactive.

Moreover, there a certain accounts in QBO that can't be inactive because they are default accounts.

For more detailed information and steps you can check this one: Make an account inactive on your chart of accounts in QuickBooks Online.

Furthermore, you'll still see the inactive accounts and their transactions when you run a report. 

Keep me updated in the comments if you have further questions about deleting your sub-account in QBO. I'm just a reply away. Keep safe and have a good one.