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.

@MelroseV  RE: Select the Action dropdown and select Make inactive.

The OP didn't ask how to make an account inactive. They want do know how to delete an account.  Did you read the question?

Also, it's drop-down, not dropdown.  Someone should tell the person who writes your pat copy/pasted answers.