hi, if we received credit note, what we don't know against which sale invoice we received. Then how we enter in gstr1 and it's important to know that credit note we received against which invoice.
It is the supplier who has to give debit note/credit note. And as the supplier he should be knowing about any return or price difference. You should confirm with your customer
Normally in the Credit Note a reference is given to the originally issued Invoice. If it is not there you will need to approach your supplier/customer to know the same and ask them to include such details henceforth in all Debit/Credit Notes for ease of understanding and clarity in the books of accounts.
Credit notes are issued by the supplier against the original invoice.. When the supplier files his GSTR 1 he has to report the credit note and while filing the Gstr 3B he has to reduce his outward liability to the extent of credit note.
If u r receiving the credit note, and if the credit note does not have a mention about the original invoice number then u may ask d supplier to revise the credit note with the original invoice number.
Further while filing your GSTR 3B you have to reverse ur ITC to the extent of the credit note received.