Can we mention freight on gst invoice. If yes then what are its effect in gst

Reply—If the contract with recipient is such that the price charged is inclusive of freight, then price charged is transaction value only and GST will be charged on the said amount. Freight cannot be charged separately. 

In absence of any contract, where transportation is provided along with the supply of goods, then transport services are taxable at the same GST rate applicable to the goods involved. The supplier cannot charge separately, different GST rates on freight charges and for the supply of goods in same invoice.