prasad Nilugal (Sr . Accountant and GST Practitioner . ) 07 August 2020
please refer Section 34 of the CGST act 2017 ( credit note and debit note )
In GSTR1 return you have to show in Table 9B credit note debit notes and Table 9C any amendments in Credit note , debit notes .
In GSTR 3B return you have less credit note amount from value of Taxable supply and if debit note you have add in value of Taxable supply .