Cancelling the GST Registration

I have GST registration for last two years. No business activity.

So, I filled nil return for all months. 

1) 04 -March 2023, I filled nil return.

2) 04-March-2023, cancelled the GST Registration. Though the online, received mail.

3) GSTR10 - All Tax liability showing '0'.  no Tax is payable.

4) going to file - GSTR10 - final return. .

Question

1) Please advise - certificate from auditor required or not? - Nil return, when tax is payable.

2) What other documents, I have need to file.?

Thanks

Venkatesan

Thanks

Venkatesan