I had already filed gstr 3b of Jan to March 2018 as NIL return but required to revise the same whether option is there to enter turnover related to that period and can I claim input for that period ?
As per section 37 ( read with rule 61) of the CGST ACT 2017, when you would be filling GSTR 3 for the respective tax period , then you can claim the ITC which you have not claimed earlier in GSTR 3B subject to the fulfillment of the conditions stipulated under section 16.