Tax invoice.

You have to provide Credit Note to your Customer. Go through Section 34 of CGST Act.

In both the condition the revenue in form of tax is neutral. But the correct way to issue credit note as prescribed in Section 34 of CGST Act.

Ok thanks for the reply, one more thing we sell goods to a distributor and they use some quantity of goods as a sample purpose and end of the month they give details of the sample, in credit note, we can reduce tax liability or not. Because we paid gst on purchase and sale also.

Yes definitely can reduce your tax liability.

Notte : In GST in term of Section 34 it's the supplier who can issue credit/debit note , as on the basis of Credit Notes issued by supplier the Recepient need to reduce his ITC.

The Recepient can issue the Credit /debit note but only for accounting purposes as the reduction /Addition of ITC by Recepient in 3B can be done only on the basis of GSTR 1 filed by supplier.