A professional invoice does two things at once: it requests payment clearly, and it documents the transaction in a way that holds up for bookkeeping, tax records, and dispute resolution. Get both right and you get paid faster with fewer back-and-forth conversations. Miss key fields and you risk delayed payments, client confusion, or compliance issues depending on where you operate.

This guide covers every field a solid invoice should include — what it is, why it matters, and how to handle the details that trip people up.

Your Business Information

Every invoice starts with your details. This section establishes who is sending the document and how you can be reached.

Business name. If you operate as a sole trader or freelancer under your own name, use your full name. If you have a registered business name, use that. This is what appears at the top of the invoice.

Logo. A logo is not strictly required, but it significantly improves how the invoice is received. A branded document looks intentional and professional. Clients who receive a polished invoice are more likely to pay on time than those who receive a generic text file.

Contact details. Include your email address, phone number, and business address. The address is especially important for tax purposes — in many jurisdictions, an invoice without a business address is not considered valid for VAT or tax deduction purposes.

Tax or registration number. If you are VAT-registered or have a business registration number, include it. In the EU and UK, a VAT number is legally required on any invoice issued by a VAT-registered business. Even if you are not VAT-registered, including your tax identification number adds legitimacy and is often required by larger clients with formal accounts payable processes.

Your Client's Information

Client name and company. Use the official name — the one on their contract or purchase order. Getting this wrong can delay payment if their accounts payable system requires an exact match.

Client address. The billing address, not the project address. For B2B clients, this is often a finance department address that is different from the main office.

Client email. The contact the invoice is going to. When in doubt, confirm this directly rather than guessing — sending a large invoice to the wrong email is a common source of payment delays.

Invoice Identification

Invoice number. Every invoice needs a unique, sequential number. Start at 001 or 0001 and go up from there. Invoice numbers are how you reference specific documents in conversation, track them in your records, and match them to payments. They are also required by law in most jurisdictions. Never duplicate a number, even if you cancel or reissue an invoice.

Issue date. The date the invoice was created and sent. This is the anchor date for payment terms — "NET 30" means 30 days from the issue date, not from when the client opened the email.

Due date. State the exact due date, not just the payment terms. "Payment due 15 May 2026" is clearer and harder to misinterpret than "NET 30." Include both if you want to be thorough.

Line Items: The Core of the Invoice

The line items section is where you describe what the client is paying for. Each line item should be clear enough that the client can match it to the work they approved.

Item name and description. Be specific. "Design services" is vague. "Brand identity design — logo, colour palette, and typography guide" is clear. The more specific the description, the less likely a client is to dispute or query the charge.

Quantity. The number of units, hours, days, or items being billed. For hourly work, this is the number of hours. For products, it is the quantity. For project-based work billed at a flat rate, this is typically 1.

Unit price. The price per unit, hour, or item. Keeping this separate from the quantity allows clients to verify the maths and understand the rate structure.

Item-level discount. If you agreed to a discount on a specific service — a loyalty rate, an introductory price, or a negotiated reduction — apply it at the line item level rather than as a blanket discount on the total. This keeps the pricing transparent and shows the client exactly what was adjusted.

Taxable flag. Not every line item is taxable. If you are providing a mix of taxable and tax-exempt services or products, mark each item accordingly. This is particularly important for businesses with mixed supply, where some services attract different tax rates.

Tax and Totals

Subtotal. The sum of all line items before tax and discounts.

Document-level discount. If you are applying a discount across the full invoice — a bulk discount, a project bonus, or an account-wide rate — apply it here as a percentage or fixed amount on the subtotal.

Tax rate and amount. Show the tax rate being applied (e.g., 20% VAT, 10% GST) and the calculated tax amount as a separate line. Clients need to see the tax amount explicitly for their own accounting records. In many countries, the tax breakdown is legally required.

Total due. The final amount the client owes, after all discounts and tax. Make this prominent — it should be the most visually obvious number on the document.

Currency. Always state the currency clearly. "$5,000" is ambiguous — "USD 5,000" or "AU$5,000" is not. If you invoice international clients in their local currency, include the currency code on every monetary amount.

Payment Terms and Instructions

Payment due date. Already mentioned above, but worth emphasising: a specific date reduces ambiguity. Common terms include NET 15, NET 30, or "due on receipt" for smaller amounts.

Accepted payment methods. Tell the client how you want to be paid. If you accept bank transfer, include your account details (account name, account number, sort code or routing number, and any reference the client should use). If you use a payment platform, include the relevant details or link.

Late payment terms. Consider including a late payment clause — for example, "Invoices unpaid after 30 days are subject to a 1.5% monthly late fee." This is both a deterrent and a legal basis for charging interest if payment is significantly delayed. Make sure this is also reflected in your contract or estimate so clients are aware of it from the start.

Purchase order number. If the client's procurement or accounts payable system works with PO numbers, include the PO number they provided on the invoice. Without it, large companies often cannot process the payment at all.

Notes and Terms

Notes. A short message to the client — a thank-you, a project reference, any context that helps them match the invoice to the work. This is also a good place for payment instructions if you want them more visible than the footer.

Terms and conditions. Standard terms that apply to your invoices — ownership of work, revision policy, confidentiality, dispute resolution. These do not need to be exhaustive on every invoice, but a brief reference to your standard terms (or a link to them) is good practice.

What a Completed Invoice Looks Like in Invofy

Invofy structures the invoice creation flow around all of the above. When you create an invoice in the app:

Your business name, logo, and contact details are pulled from your business profile automatically
Client details are pulled from your saved client record
Invoice number is assigned sequentially and is editable
Each line item has a name, quantity, unit price, item-level discount, and taxable flag
The document shows a subtotal, document-level discount, tax amount (at the rate you set), and total
Due date, notes, and payment terms all have dedicated fields
The currency is set per invoice and displayed with locale-aware formatting

Once the invoice is filled out, you choose from three PDF templates — Classic, Modern, or Minimal — and set your brand color. Invofy generates the PDF and opens the iOS share sheet so you can send via email, message, or any other app on your phone.

A Few Things Worth Knowing

Sequential invoice numbers are a legal requirement in most places. Do not restart the numbering each year or use duplicate numbers. If you void an invoice, keep the number in your records marked as void rather than reassigning it.

Your invoice is only as clear as your descriptions. Vague line items create queries. Queries delay payment. Write each description as if the person reading it has no context for the work — because sometimes, that is exactly who reviews invoices in a client's finance department.

Keep copies of everything. In most jurisdictions, you are legally required to retain invoice records for at least three to seven years. Invofy stores all your invoices in the app, and you can export a CSV at any time for your own records or to hand to an accountant.

A well-structured invoice is one of the simplest ways to look professional and get paid without friction. Get the fields right once, and every invoice you send from that point on is faster and cleaner. If you want to create invoices like this from your iPhone or iPad, download Invofy — all of these fields are built into the mobile workflow.

How to Write a Professional Invoice: Everything You Need to Include