The Informal Invoice is a commonly used commercial document in Hong Kong's business environment, particularly suitable for small to medium-sized enterprises and straightforward business transactions. This document type serves as a less formal alternative to a full commercial invoice while still maintaining compliance with Hong Kong's business documentation requirements. It includes essential information such as business registration details, transaction specifics, and payment terms, making it suitable for routine business operations. The informal invoice is particularly useful when immediate billing is required, or when the transaction doesn't necessitate a more complex formal invoice structure. While less formal, it still serves as a valid business record under Hong Kong law and can be used for basic accounting and record-keeping purposes.

1. Invoice Header: Company logo, 'INVOICE' label, and invoice number

2. Seller Details: Legal business name, address, contact information, and Business Registration Number

3. Buyer Details: Client's name, company (if applicable), billing address, and contact information

4. Invoice Details: Invoice date, due date, and payment terms

5. Item Description: Detailed list of products/services, quantities, unit prices, and subtotals

6. Total Amount: Subtotal, any applicable taxes or discounts, and final total amount

7. Payment Instructions: Bank details or other payment methods accepted