GST Inward credit

you can  upload  Invoice  in the month of June 2017  and claim  Input Tax Credit  as per section  section 16  subsection 4  of the CGST act 2017 , subject to payment of tax made by supplier to the GOVT collected form you  , and file monthly retrun  as per section 16 (2)  of the CGST act  2017

please confirm with others also.

Yes you can book the bill in March and claim refund in May. Last date for claiming ITC is 20th Oct, 18 or date of filing of Annual return whichever is earlier for F.Y. 2017-18.