Is there an option to close or locked the previous year in quickbooks online?

there is no such option in QBooks for 2020 Mac Desktop

Not to worry, ep111. I've got just the steps you'll need to set a closing date and password to prevent any accidental changes that will affect your books.

Kindly follow the outlined steps:

1. Go to the Company menu and choose Users and Passwords.
2. Select  Set Closing Date.
3. Enter Closing Date and Closing Date Password.
4. Click OK and close the Users and Passwords window.

For more details, please check out the set or change a closing date and closing date password in Quickbooks Desktop.

Keep me posted on the results in the comment section below. I want to ensure everything is working well for you.