I am trying to enter a supplier invoice dated last year. I have closed the last year and want the entry to be posted in the current year.

Hi there, @nimal-atheray.

Allow me to share some details about the supplier's invoice that was dated last year.

Since you've mentioned that it was dated last year and you have closed your company's books. It's not advisable to make the  entry for last year. I'd suggest speaking to your accountant about this matter to make sure you're in compliance with your country's VAT system.

To know more about how to manage supplier's expense transactions, you can check out this article: 

Enter, edit, or delete expenses in QuickBooks Online.

I've added this article you can use in the future: Common VAT Codes. 

You're always welcome to tag my name in the comment section if you have other concerns or questions. I'd be happy to back you up. Take care.