Direct Sale from Inter State Branch

Dear Members,

My Client is running a Partnership Firm registered in Mumbai carrying the sale of goods business and enrolled under GST in Mumbai. Now, he wants to open the Branch in Rajasthan for which goods can be dispatched directly from Rajasthan to different states. Order will be placed and billing will be generated from Mumbai and the order will be forwarded to Rajasthan Branch to dispatched the goods to the customer. 

In the Above Scenario, 

1. Applicability of GST in case of Bill raised from Mumbai Office and Goods Dispatched from Rajasthan. (Tax Invoice & Bill of Supply)

2. Records to be Maintained between the Branch office of Rajasthan and Mumbai.

Your Reply will be appreciated.

Thanks