How to Write a Invoice

Writing an invoice is straightforward when you follow a checklist. The goal is one clear, professional page that tells the client exactly what to pay and how.

To write an invoice: 1. Use a clean template or a free invoice generator like InvoiceSonic 2. Add your business name, ABN, and contact details at the top 3. Generate a unique sequential invoice number 4. Add today's date as the issue date 5. Enter the client's name and billing address 6. List each product or service with description, quantity, and rate 7. Calculate the subtotal 8. Add GST (10%) if you're registered for GST, and label the invoice "Tax Invoice" 9. Show the final total amount payable 10. Set payment terms — typically Net 14 11. Add bank, BPAY, or PayID details 12. Save as PDF and send to the client

Keep a copy of every invoice for at least five years for ATO records. Sending invoices the same day work is completed, and following up 2–3 days before the due date, is the simplest way to keep cash flow healthy.