Furnishing details of outward supplies requires electronic submission by registered persons and allows limited rectification and commissioner extensions. Registered persons, excluding Input Service Distributors, non-resident taxable persons and certain composition or TDS/TCS taxpayers, must electronically furnish details of outward supplies (invoices, debit/credit/revised invoices) in the prescribed form and communicate them to recipients by the prescribed monthly deadline; the Commissioner may extend the time for specified classes. Recipients must accept or reject communicated details within a limited response window, which amends the supplier's return. Errors in unmatched details must be rectified and any tax and interest paid, subject to a cut-off on filing the September monthly return for the relevant financial year or the annual return, whichever is earlier.