Turnover not declare

Credit or Cash invoice, not declared in GST return is related to which year ??

For 2019-2020

As per provision of GST law, you can rectify your any mistake / omissions relating to inward Supplies (ITC) or outward Supplies in next year before due date of filing return of September,next year or due date of filing Annual return of that year, whichever is earlier.

So, as per above provision, You can show your invoices of F.Y 2019-20 not shown/missed to show in F.Y 2019-20, in GSTR 1 or in GSTR 3b in any month up to September, 2020 before due date of filing return of September, 2020 (i.e 20th October, 2020) and pay tax thereon along with interest.

Yes sagar ji but my itc in credit balance ican adjusted, and sagar ji interest payable on net tax balance or on sales tax?

Yes, you can use/adjust your ITC in credit Ledger to set of the output liability.

The 39th GST Council meeting dates 14/03/2020 declared that the interest on delayed GST payments would be applicable only on net cash tax liability after the deduction of the available input tax credits. This change will be applicable retrospectively with effect from 1 July 2017, the date on which GST legislation came into forces.

In 2019, the government had amended Section 50 of the CGST Act to clarify that the interest will be levied on a net basis.

Amendment to GST Act yet to be notified, although it has been clearly decided that interest will be applicable on tax payable in cash only u/s 50 of CGST Act restrospectively from 1st July 2017.

Suggest to discharge interest on net tax liability only (after ITC set off)

Thanku so much sagarji

Most welcome................Amit ji