GSTR1 filed with wrong invoice details

Amend the invoice in your next GSTR-1 under amended B2B Table

THANK YOU ALL, My question is I made it in August-2020, whereas it is March-2021. Can I do it in march gstr1 when mistake is of August 2020

Yes you can do it.......

There are two ways to adjust this:
1 Go for B2B amendment and change the GSTIN of counterparty
2 Issue a credit note to client B and a fresh invoice to client A. Please note in option 2 you need to issue a backdated credit note and backdated invoice