Sale during course of export is exempt from CST. As per section 5(3) of CST Act, penultimate sale is also deemed to be in course of export and is exempt from CST. Dealer actually exporting the goods has proof of export like customs documents, bank certificate, airway bill/bill of lading, shipping bill etc. However, the penultimate seller does not have any direct evidence to prove that his sale is exempt from tax. In such cases, the actual exporter has to issue a certificate to the penultimate seller in form H. The blank ‘H’ forms are to be obtained from sales tax authority by the final exporter.
Agreed with above expert, but in my opinion you have to keep in mind that you can not change the shape of material. e.g. if you purchase raw material against form 'H' and after conversion of such raw material into other shape i.e., finished goods you exports the finished goods. In this case form 'H' is not applicable.