Tax rate on Invoice

Arunachalam (Proprietor) (186 Points)

08 January 2019  
Hi All:

One of my friends purchases solar panel and battery of tax rates 5 and 18 respectively. He assembles and installs it for his customers. Question is, when he includes those items on the invoice, does he need to show the tax rates of each item as he purchases along with his service charge 18percent? or he should show 18percent for all items including his service charge.

Please advise.

Thanks.