Declaration Form C register records receipt and issue details under Central Sales Tax (Delhi) Rules, ensuring complete transaction traceability. Register of Declaration Forms requires logging receipt and issuance of Declaration Form C, recording authority from whom received, book and serial numbers, date of issue, purchaser identity and order reference, Declaration Form C number and state, description and value of goods, seller's cash memo/challan, carrier receipt, surrender to Value Added Tax authority, and remarks to provide a documentary trail for inter state sales compliance.