How to write an invoice

To write an Australian tax invoice, include seven details the ATO requires: words showing it is intended to be a tax invoice, your identity, your ABN, the issue date, a description of what was sold with quantity and price, the GST amount, and the extent each sale is taxable, plus the buyer’s identity or ABN for sales of $1,000 or more. Then add what gets it paid: a unique invoice number, the buyer’s purchase order, a due date, payment terms and bank details with a reference.

Tax invoice or plain invoice

business.gov.au describes two main kinds. GST registered businesses must use tax invoices, which show the GST on what was sold. Businesses that are not registered use regular invoices that show no tax, and must not use the words tax invoice. A third, less common kind, the recipient created tax invoice, is issued by the buyer and only allowed in certain industries.

If you are registered, the ATO says you must give a tax invoice within 28 days when a customer asks, unless the sale was $82.50 including GST or less. In practice most businesses send one with every sale.

The note on what a tax invoice is defines the term; this guide is about writing one that is both valid and quick to pay.

The details the ATO requires

For taxable sales of less than $1,000, the ATO says the tax invoice must include enough information to clearly determine seven details:

1. that the document is intended to be a tax invoice
2. the seller’s identity
3. the seller’s ABN
4. the date the invoice was issued
5. a brief description of the items sold, including quantity if applicable and price
6. the GST amount payable, shown separately, or a statement that the total price includes GST where the GST is exactly one eleventh of the total
7. the extent to which each sale on the invoice is a taxable sale

For sales of $1,000 or more, the invoice must also show the buyer’s identity or ABN. The ATO notes that an invoice meeting the $1,000 requirements can be used for smaller sales too, so a single template that always includes the buyer is simplest.

Where an invoice mixes taxable and non taxable items, such as GST free goods, the ATO says it must clearly show which items are taxable, as well as the GST payable and the total amount payable.

The invoice example from a fictional Melbourne design studio shows all of these. The heading reads Tax invoice. The seller’s ABN sits in the letterhead and again in the footer. The buyer, a property firm in Brisbane, is named with its address and ABN because the total is well over $1,000. Six service lines, from brand strategy at $4,000 to project management at $2,170, add to a subtotal of $17,670. GST at 10% adds $1,767.00 and the total is $19,437.00, all in the same table.

Numbering and dates

Preparation starts before the invoice. business.gov.au’s invoicing guide suggests collecting the customer’s details when they order, including their name, address, phone, email and ABN, so everything needed to invoice them is already on file, and setting clear rules for when and how customers should pay. It also recommends adding a unique invoice number, your contact details and when and how you want to be paid, even though those are not among the details the law requires on a tax invoice.

An invoice number is not one of the ATO’s listed details, but you cannot run a business without it. Use one sequence that never repeats, such as INV-2026-0217 in the example, and never reuse the number of a cancelled invoice. A correction is a credit note that references the original, followed by a new invoice.

Put three dates or references where the payer looks first: the issue date, the due date and the buyer’s purchase order number. The example sets them in one block beside the bill to address: issue date 18 August 2026, due date 1 September 2026, purchase order PO-8842 and terms of 14 days. An accounts payable clerk matching the invoice to an order finds everything in one place, which is where most payment delays start or end.

Payment details and terms

Make paying the invoice one step. The example gives the bank, BSB, account number and a payment reference in their own block under the table, with a note asking the payer to use the invoice number as the reference. Without the reference, a payment arrives with nothing to match it to.

State the terms plainly, as a number of days or a date. If you intend to charge interest on overdue amounts, the rate should already be in the contract or the accepted quote; the example adds a note that interest may be charged at 2.5% a month on overdue invoices. The late payment interest clause explains why the agreement, not the invoice, is where interest is best set.

Layout an accounts team can process

The Australian Small Business and Family Enterprise Ombudsman’s invoice tips focus on the practical side of getting paid, especially by large businesses. Before sending, find the right contact in the accounts area and check what they need to process your invoice. Double check that the details match the order and the delivery receipt. Confirm the invoice has been received. Ten days before it is due, check that it has been processed. If payment is one or two days late, contact the accounts area to ask whether something is stopping it.

On the page itself that means:

• the seller at the top, the buyer and the invoice facts beside or below
• one line per item, with quantity, unit price and amount in right aligned columns
• subtotal, GST and total as the last rows of the same table
• payment details directly under the total
• nothing on the page that is not needed to pay it

The requirements table

The table at the end of this article lists thirteen details, when each is required, and how the Lantern Creative example shows it. The first eight rows are the ATO’s tax invoice requirements, including the buyer’s details from $1,000; the rest are what an accounts team needs. If a row is missing from your template, add it before the next invoice goes out.

Once invoices go unpaid, a statement of account lists everything open with ageing, and the guide on quote vs invoice vs proforma invoice explains where the invoice sits after a quote.

Common mistakes

Tax invoice from an unregistered seller. business.gov.au says a business that is not registered must not use the words tax invoice, and charging GST you are not registered for creates a real liability.

No buyer details on a large sale. From $1,000 the buyer’s identity or ABN is required.

A total that does not reconcile. Lines, subtotal, GST and total must add up; buyers reject invoices that do not.

Missing purchase order. Many larger buyers will not pay an invoice without their PO number.

Editing a sent invoice. Issue a credit note and a new invoice, so both sets of books agree.

Build it

An invoice speaks for a sender, so a document here carries a letterhead, in one of four styles: masthead, ledger, monogram or underline. A cover page is never added to an invoice, receipt or letter, so it starts straight with the letterhead and the invoice facts. Input fields are not used in documents, so every line, rate and total is written as content and should be checked like any typed figure.

The AI chat edits text only, so it can reword a line description or the payment note, while table rows are added in the builder. The page on letterheads shows the four styles, and the tutorial on creating a document with AI covers producing the first draft.