Am trying to close period in Quick books for March 2020. But closing option is not available?

Thanks for dropping by, @finance-ol.

You may be logging in to QuickBooks as a standard user. Please make sure that you are set up as a company admin or the master admin to close the books.

Besides, to ensure the book is closable, you have to check the Close the books box and enter the password in the Accounting section under Advanced settings.

I've added an article as your reference before closing your book in QBO: Close your books to lock past transactions. It includes the year-end guide and checklist link.

Please feel free to comment on this post if you have more questions. I'm always here to assist you. Have a good one!