i have existing account need to make a new one

Hello there. Thank you for posting your concern here in the Community. I can provide some details about deleting and creating a new account.

You'll have the option to purge your account if you're using QuickBooks Online Plus, Essentials, and Advance and your company data file is less than 60 days if you mean by deleting and creating a new account is your company file. That way, the system will delete all the data entered into the company, and you can't restore or reverse them. 

However, if the company file is already 60 days or older, you need to manually delete all those transactions or cancel your account and start a new subscription.

To purge the data, follow the steps listed below:

1. Log in to your QuickBooks Online account.
2. Change the URL to include /purgecompany.
3. You can refer to this Example: if the URL shows https://...qbo.intuit.com/app/homepage, change it to: https://...qbo.intuit.com/app/purgecompany.
4. You can see a summary of the items to be deleted in the next window.
5. Type the word YES once the data gets deleted, then click OK.
6. Select the Wipe Data option once your selections are complete.
7. Then once the deletion is complete, you will be rerouted to your home page.

You may refer to this article for more details: Delete your data and start over in QuickBooks Online.

If you're referring to deleting an account you mistakenly created in your Chart of Accounts, you can inactivate it so it won't appear on the list and your reports. Let me show you how:

1. Go to the Accounting menu and select Chart of Accounts.
2. Look for the account and click the drop-down arrow beside the View register.
3. Select Make inactive.
4. Confirm the action by clicking Yes.

I'll add this article as your reference in removing accounts from your COA: Delete an account on your chart of accounts in QuickBooks Online. It includes how to disconnect accounts from online banking.

Additionally, please check out this article to set up a new account in your chart of accounts: Add an account to your chart of accounts in QuickBooks Online.

Furthermore, there are also default or special accounts that can't be deleted, edited, or merged in QuickBooks Online. Please check this article for more details: Manage default and special accounts in your QuickBooks Online chart of accounts. In this article, we’ll show you which default accounts are created for each business entity, and which accounts you can edit, merge, or make inactive.

Keep me posted if you mean anything else or if you have other queries regarding QuickBooks. I'll be happy to take care of them for you. Have a good one!