How do I start 2021 with a zero balance in payroll???

Thanks for reaching out, info-crescentcit.

I'll help you out in zeroing the accounts balances in QuickBooks Online.
 

You'll want to create a journal entry for adjustment to zero the accounts.  Here's how to create a journal entry:

1. Go to the + New button and select Journal Entry.
2. select an account from the Account field. Depending on if you need to debit or credit the account, enter the amount in the correct column.
3. On the next line, select the other account you're moving money to or from. Depending on if you entered a debit or credit on the first line, enter the same amount in the opposite column.
4. Check the amounts - you should have the same amount in the Credit column on one line and the Debit column on the other. This means the accounts are in balance.
5. Enter information in the memo section so you know why you made the journal entry.
6. Select Save and new or Save and close.

You can check this article to learn more about creating a journal entry: Create a journal entry in QuickBooks Online.

Also, you'll want to start a new QuickBooks Online account.

Feel free to come back here if you have questions about managing your account. I'll be right here to help you with everything in QuickBooks.