Provisions relating to refund are contained in section 54 of the CGST Act, 2017. It provides for refund of tax paid on zero-rated supplies of goods or services or on inputs or input services used in making such zero rated supplies, or refund of tax on the supply of goods regarded as deemed exports, or refund of unutilized input tax credit. Identical provisions exist under the IGST Act, 2017 and relevant SGST/UTGST Acts.
(FAQ 4: HANDICRAFTS)