New to online qb..where do I set password to lock closed tax year so transactions cannot be altered?

It's nice to have you in the Community, @2011-dennis-acct.  I’m here to walk you through the steps on how to close your books in QuickBooks Online.

Closing your books prevents unwanted changes before filing your taxes. This secures your records, ensuring that no one can alter your accounting data before the end of the fiscal year.

Here’s how:

1. Go to Settings  and then select Accounts and Settings.
2. Select the Advanced tab.
3. Select Edit ✎ in the Accounting section.
4. Select the Close the books checkbox.
5. Enter a closing date. Give yourself a comfortable deadline. You shouldn't need to edit any transactions before this date. Your new bookkeeping work will start after this point.
6. Select the Allow changes after viewing a warning and entering a password option from the drop-down menu if you want to require a password before editing your closed books.
7. Select Save and then Done.
   
   

Additionally, please this link for more details about closing books in QBO.

If in case you want to check out our Yearend guide and checklist, please see this article for further details.

Get back to me here if you have further questions about the information above. I'd be more than happy to answer it for you. Have a nice day.