Furnishing details of outward supplies: mandatory electronic reporting, recipient communication, and amendment controls under GST. Every registered person, excluding specified categories, must electronically furnish details of outward supplies for each tax period and communicate them to recipients within prescribed timelines; the Commissioner may extend these deadlines. Recipients have a limited acceptance/rejection window that amends furnished details. Suppliers must rectify errors or omissions in unmatched entries, pay resulting tax and interest, and cannot rectify after the statutory cut-off linked to the September return or the relevant annual return. 'Details of outward supplies' include invoices, debit notes, credit notes and revised invoices.