how to delete an account created mistakenly?

Hi there, ppminvsvs. Allow me to guide you in deleting an account in QuickBooks Online.

If you've never used this account or its balance is $0, you can easily delete or make it inactive. To do this, you can follow the steps below:

1. Go to the Gear ⚙ icon, then choose Chart of Accounts.
2. Find the account you want to remove.
3. Click on the Action ▼ dropdown and select Make inactive.

Otherwise, if the account you created already has a balance, delete all linked transactions before deleting the account. I've added this article for more details on how to manage accounts in your chart of accounts: Make an account inactive on your chart of accounts in QuickBooks Online.

You can also use this link as a reference to make sure you understand the different account types and detail types: Learn about account types and detail types in QuickBooks Online.

If you need assistance or have follow-up questions about your chart of accounts, let me know in the comment section below. Have a great day!