Electronic cash and credit ledgers determine receipt, utilisation and priority of GST payments and input tax credit application. Section 49 mandates that prescribed electronic payments be credited to an electronic cash ledger and self-assessed input tax credit to an electronic credit ledger; balances in the cash ledger may be used for tax, interest, penalty, fees and other amounts, while credit ledger balances may be used for output tax under this Act or the Integrated Act, subject to prescribed conditions and time limits. The section sets a priority order for utilisation of integrated, central, State and Union territory tax credits, restricts certain cross-utilisation, provides for refunds of residual balances, requires an electronic liability register, prescribes the order of discharging dues, and creates a rebuttable presumption that tax has been passed to the recipient.