The C form is issued for the inter state sales . Inter state sales means inter state movement of the goods . The goods should have physcially crossed the state boarder . Thus the consignor and consignee should be different states . The C -from can be issued even though both the seller and buyer are in the same state , provided the goods as a result of sales transaction moves from one state to another state . This situation is well covered under section 3(a) and 3(b) of the Central Sales Tax Act .