How can I change the financial year so that it does not end on the last day of a calendar months.my business has a financial year starts on 6th April ends on the 5th

I can show you how to change the financial year of your account, @wpbcharles-aol-c.

You can only set the first month of your financial year from the Account and Settings.

Follow the steps below:

1. Go to the Gear icon ⚙ and choose Account and Settings.
2. Click on Advanced and proceed to the Accounting section.
3. Set the First month of fiscal year. 
4. Click on Save and then Done.

Here's the QuickBooks Online year-end guide and checklist article for more information about updating your financial year.

Once you're done, you can close your books to prevent changes to past transactions. You can check this guide for detailed guidance: Close your books in QuickBooks Online.

Let me know if you need further help with updating your financial year in QBO. I'm always here ready to help. Take care and have a great rest of the day!