You can purge your QuickBooks Online (QBO) account to start over. However, this process will only take effect if your account aged is less than 60 days. Also, it only works for QBO Plus and Essentials version.
Log in to your QuickBooks Online account as an admin.
Change the URL in your browser's address bar. For example:
4. In the Wipe Company Data page, select the correct business type for the first question.
5. For the second question, select Create an empty chart of accounts.
6. Click Wipe Data.
But if your account is older than 60 days, you'll want to cancel your QBO account, and start a new subscription. For more guidance, feel free to check out this article for the detailed steps and information: Delete your data and start over in QuickBooks Online.