As per the provision u/s 16(4) of CGST Act, 2017 “A registered person shall not be entitled to take input tax credit in respect of any invoice or debit note for supply of goods or services or both after the due date of furnishing of the return under section 39 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.”
As per the aforesaid provision, the time limit for taking input tax credit for the financial year 2018-19 is up to the filing of return (GSTR-3B) for the month of September 2019. The due date of filing of GSTR-3B for the month of September 2019 is 20th of October 2019.
So make sure to Reconcile Data as per your books with GSTR 3B and GSTR 2A on or before 20th October 2019 in order to get all the benefits under GST