Invoicing customers

Key requirements

A tax invoice generally goes to a registered customer within thirty days of supply; prescribed-goods customer accounting uses its own invoice. For total payable at most S$1,000 including GST, a simplified invoice can use the required supplier, date, identifier, description, total and inclusive-tax statement. Non-registered customers can receive receipts, while credit and debit notes document later adjustments. Keep issued and received documents for five years. BCRS deposits remain separately identified as non-taxable if included. InvoiceNow transmission phases are an additional obligation and do not replace content requirements. Self-billing requires the applicable arrangement, not unilateral buyer-created invoices.