Query 17-18

Your query is not cleared...

yes you can book the purchase in 17-18 as your books are not audited..

further Section 16(4) of CGST Act says that a taxable person shall not be entitled to take input tax credit in respect of any invoice or debit note for supply of goods or services after furnishing of the return under section 34 for the month of September following the end of financial year to which such invoice or invoice relating to such debit note pertains or furnishing of the relevant annual return, whichever is earlier.

In simple words, you can book the tax invoice in month of March, 2018 so that balance as per ur books and party books match with each other & claim the input tax credit while filing your GSTR 3B till September,2018 or filing of annual return for FY 2017-18 which ever is earlier.

agree with Abhay Gupta

Yes, I agree with CA Abhay Gupta sir.
follow his advice.