You can record purchase returns (both local and interstate) against an earlier purchase transaction under GST using a debit note.
To record purchase return using a debit note
1. Go to Gateway of Tally > Accounting Vouchers > Ctrl+F9.
2. Original invoice no: Enter the invoice number of the original purchase transaction against which you are recording the purchase return.
3. In Party’s A/c Name, select the party from which the original purchase was made.
4. Select the central and state tax ledgers.
5. Provide GST details: Enable this option if you want to enter additional details about the purchase return.
Similarly, you can record purchase returns against an interstate purchase by selecting the relevant party, purchase ledger, and integrated tax ledger.