FOC Invoice

We have send some sample through Transporter by   FOC INVOICE  which Taxable Value come  Rs. 8000.00 +  IGST(18%) 1440.00=Rs. 9440.00(Gross Value)

Now our Question is -

1. GSTR 1 & GSTR 3B  Return where we show the above FOC Invoice ?
2. Can we pay IGST(Rs. 1440.00) if Yes then Payment Procedure?