invoice format, place of suply

sujit hegde (9 Points)

24 July 2017  
Company "A" has a location in Bangalore purchases the goods from Company " B"of Mumbai for the purpose of export. B company purchases the goods from company " c" of kalkatta.& directly sent the goods to Port for export. here neither the buyer nor the seller received the goods in their situated office.

so my doubt is what is the place of supply now? Bangalore? & what kind of gst invoice to be raised by company A,B , c respectively?