Furnishing details of outward supplies requires electronic submission, recipient communication, acceptance window and rectification procedures. Every registered person, except specified exclusions, must electronically furnish details of outward supplies in the prescribed form and communicate them to recipients, subject to a restricted sub-period and possible Commissionerial extensions. Recipients must accept or reject communicated details within the prescribed window, amending supplier returns accordingly. Suppliers with unmatched details must rectify errors, pay tax and interest in the relevant period's return, and cannot rectify after filing the September return following the financial year or the relevant annual return. 'Details of outward supplies' includes invoices, debit notes, credit notes and revised invoices.