Missing invoice Pertaining to FY 2017-18

Hi

There is one invoice of march 2018  and which is neither shown in Gstr 1 nor to Gstr 3b. and also not shown in September 2018. can we take in march 2019 pertain to march 2018 invoice.

One more

there is one interstate invoice but gstr3b i have shown as intra state and paid taxes , filed return. but gstr1 i have taken as interstate sales. how to rectify the mistake

There are Invoices of OCT 2017 which was missed during GSTR 1 but tax has been paid in GSTR 3B can those invoices be uploaded now in June 2019. If yes how as it is creating a difference in GSTR 9