Applying gst tax

I MADE AN INVOICE OF A CLIENT WITH 1000 PCS OF 1 RE VALUE WHICH COMES TO 1000 RS. I PAID COURIER CHARGES ON HIS BEHALF OF 300 RS .

SO I MADE INVOICE BILL AS 1000 RS GOODS + 300 RS COURIERS EXPENSES AND ADDED 120(12% OF GOODS AS GST) AND 54 (18% OF COURIERS AS GST IN BILL AND SENT TO THE CLIENT,

NOW I AM NOT SURE IF I HAVE RAISED THE BILL PROPERLY