Karnataka GST Rules: portal-based registration, composition levy rules, valuation, input tax credit, invoicing, returns and refunds. The Rules implement procedural and substantive GST mechanisms: composition levy eligibility, intimation and withdrawal processes with prescribed forms and rates; electronic registration, verification, migration and cancellation procedures using PAN and portal based forms; hierarchical valuation rules including special valuations for foreign exchange, insurance and second hand goods; comprehensive input tax credit documentary, attribution, reversal and transfer rules with ISD distribution mechanics; mandatory invoicing, record keeping and delivery challan requirements; electronic return, matching and reconciliation systems (GSTR series); audit, assessment and appeal procedures; and electronic ledger, payment and refund processes with specified formulas and forms.