What to Include on an Invoice: The Complete Field List
Key points
- Nine fields are required in practice: your details, client details, invoice number, issue date, due date, line items, subtotal, total due, and payment terms.
- A purchase order number is optional legally but mandatory at many companies. Ask before you invoice.
- Tax registration numbers are only included if you are actually registered. Never invent one.
- Fields that do not apply should be left off. A shorter invoice is read faster and paid faster.
Which fields does every invoice need?
Nine fields carry the whole document. Each one answers a question the person paying has to answer before the money can move, which is why leaving one out stalls the invoice rather than merely looking untidy.
| Field | What it answers | Example |
|---|---|---|
| Your business name and contact details | Who is asking to be paid, and how to reach them | Meridian Studio, hello@meridian.studio |
| Client name and address | Which legal entity owes the money | Wayne Enterprises Ltd |
| Invoice number | How both sides reference this bill later | INV-014 |
| Issue date | When the payment clock starts | 6 August 2026 |
| Due date | When payment is actually late | 5 September 2026 |
| Line items | What is being charged for | Art direction, 6 days × $950 |
| Subtotal and tax | How the final figure was reached | $10,500 + 7.5% tax |
| Total due | The single number to pay | $11,287.50 |
| Payment terms and details | How and by when to pay | Net 30, bank transfer, account 0123456789 |
The required fields, and the question each one answers for the person paying.
Which fields are optional but worth adding?
These are not required, but each one removes a reason for the invoice to come back to you with a question attached.
- Purchase order number. Optional in law, effectively mandatory at any company that issues POs.
- Tax registration number. Required if you are registered, because the client needs it to reclaim the tax.
- Your logo. No functional purpose, but it makes an invoice recognisable in an inbox of dozens.
- Notes. The place for bank details, a thank you, or context on a line item.
- Terms and conditions. Late fees, cancellation policy, ownership of work until paid.
- Shipping address. Only when goods go somewhere other than the billing address.
- Amount already paid. If a deposit was taken, show it and show the remaining balance, or you will be asked.
How should line items be written?
A line item should make sense to someone who was not involved in the work. The person approving the invoice is usually not the person who hired you, and a description they cannot interpret becomes an email rather than a payment.
Write "Homepage design, 3 rounds of revisions" rather than "Design". Write "Art direction, 6 days" rather than "Consultancy". Where a rate is hourly or daily, show the quantity and rate separately so the arithmetic is visible.
Where does tax go on an invoice?
Tax is shown after the subtotal and after any discount, then added to reach the total. The standard order is subtotal, discount, tax on the discounted amount, shipping, total due. Charging tax on a figure before the discount overstates what is owed.
Only charge tax if you are registered to collect it. Rates and rules differ by country and sometimes by what you are selling, so check your own tax authority rather than copying another business's invoice.
What should you leave off?
Anything that does not apply. Empty fields labelled "Shipping" or "PO Number" on an invoice that has neither make the document harder to scan and suggest it was produced without attention.
Also leave off bank details you do not want reproduced, personal home addresses where a business address exists, and any figure you cannot substantiate if queried.
Frequently asked questions
Does an invoice need a tax number?
Only if you are registered for a sales tax such as VAT or GST. If you are, the number is required for the client to reclaim the tax, and leaving it off will get the invoice returned. If you are not registered, do not invent one and do not charge tax.
Is a purchase order number required on an invoice?
Not legally, but many companies will not pay without one. If your client uses purchase orders, ask for the number before you invoice and put it on the document. A missing PO number is one of the most common reasons an invoice sits unpaid at a larger company.
Do I need to include a shipping address?
Only when goods are being delivered somewhere other than the billing address. For services it is unnecessary. Adding fields that do not apply makes an invoice harder to read, not more professional.
What is the difference between an invoice and a receipt?
An invoice requests payment before it has been made. A receipt confirms payment after it has been made. The same job can produce both: an invoice when you bill, and a receipt once the money arrives.
Put this into practice. The invoice generator is free, needs no signup, and produces a PDF with real selectable text in 104 currencies.
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