What to include on an invoice

The essentials on every invoice

• The word “Invoice” at the top, so it isn’t mistaken for a quote or receipt
• Your business name, address and contact details (and your logo, if you have one)
• Your client’s name and billing address; for a company, its registered name
• A unique invoice number that follows a sequence
• The invoice date (the date you issue it)
• A description of each product or service, with quantity, unit price and line total
• The subtotal, any discount, tax and shipping, and the total amount due
• The currency, if it isn’t obvious from the context
• The due date or payment terms, such as “Net 30”
• How to pay: bank details, a payment link or accepted methods

Extra details tax rules often require

Once you are registered for a sales tax such as VAT or GST, an invoice is also a tax document, and most countries list what it must contain. In the European Union, for example, a full VAT invoice must show your VAT number, the date of supply if it differs from the invoice date, the net amount per tax rate, the VAT rate and the VAT amount. Selling to a business in another EU country often means adding the customer’s VAT number and a note that the reverse charge applies.

Other countries have similar lists. The UK follows rules close to the EU’s; India’s GST invoices need the supplier’s GSTIN, the place of supply and HSN or SAC codes; Australia requires an ABN on tax invoices. The exact rules change over time, so check your tax authority’s website or ask an accountant before you rely on a template.

Details that help you get paid faster

• The client’s purchase order (PO) number, if they gave you one. Many accounts departments won’t pay without it
• A contact name in the client’s accounts team
• A short, specific description of each line, not just “services”
• The period or project the invoice covers
• Your late-payment terms, if you have them in your contract
• A thank-you note: it costs nothing and keeps the tone friendly

Common mistakes that delay payment

The most common reasons invoices get stuck are missing or wrong client details, a missing PO number, a vague description the approver doesn’t recognise, and totals that don’t add up. Duplicate invoice numbers cause problems in both your books and your client’s.

Before you send, check the client’s legal name and address against your contract, make sure the number hasn’t been used before, and read the line items as if you were the person approving them. A generator that calculates the totals for you removes the arithmetic errors.

A simple invoice example

Here is how the essentials fit together on a short service invoice. Your layout can differ; what matters is that every item is present and easy to find.

INVOICE INV-2026-014 Date: 3 October 2026 Due: 17 October 2026 (Net 14) From: Rivera Design Studio, 12 Harbour Road, Bristol BS1 4XY VAT no. GB123456789 To: Northwind Ltd, Accounts Payable, 80 King Street, Leeds LS1 2HQ PO number: NW-7781 Brand refresh – logo and colour palette 1 × £1,800.00 £1,800.00 Social media templates 10 × £45.00 £450.00 Subtotal £2,250.00 VAT 20% £450.00 Total due £2,700.00 Pay by bank transfer to: Rivera Design Studio, sort code 00-00-00, account 12345678. Thank you for your business!

Deposits, part payments and corrections

If the client paid a deposit, show it on the final invoice so the balance is clear: the full total, the amount already paid and the balance due. Each payment request should still be its own numbered invoice.

If you need to correct or cancel an invoice you have already sent, don’t edit it. Issue a credit note that references the original invoice number, then send a new, correct invoice. This keeps your records and the client’s in step.

Putting it together with BillOak

The BillOak editor has a field for each essential: your details and logo, the client’s details, invoice number, date, payment terms and due date, PO number, line items, discount, tax, shipping, amount paid, notes and terms. Write “Net 30” in Payment Terms and the due date is filled in for you. Extra details such as a VAT number or bank account fit in your address block or the notes, and appear on every PDF.