HOW TO ADD FREIGHT AMOUNT IN SALES INVOICE

DEAR SIR

IF WE CHARGE/ADD  FREIGHT AMOUNT-(COURIER CHARGES, TRANSPORT CHARGES ) IN SALES INVOICE THEN HOW WE CREATE FREIGHT HEAD AS A PRODUCT OR AS A EXPENSES ? AND WHAT IS HSN CODE OF FREIGHT & TAX RATE ( IF TWO DIFFERENT RATE PRODUCT ADD IN INVOICE I.E.ONE IS 18% AND 2ND IS 28%) OF FREIGHT AND WHAT IS ITS GROUP- IT IS UNDER GOODS OR IT IS UNDER SUPPLY. WHAT IS CORRECT DISPLAY OF FREIGHT PORTION IN FORM GSTR1