Invoice Must-Haves: What Every Professional Invoice Should Include

Your Business Information

The top of your invoice should clearly identify who the invoice is from. Include:

• Business name: Your trading name or legal entity name. If you operate under a different trading name from your legal name, include both where required by law.
• Business address: Your registered business address or correspondence address. In the UK, limited companies must show their registered office address on all business documents.
• Contact email and phone number: Make it easy for the client to reach you if they have questions about the invoice. Payment queries directed to a dead email address are a common source of delays.
• Company registration number: Required for UK limited companies and many other jurisdictions. Shows legitimacy and is required for legal compliance in several countries.
• VAT/GST/Sales tax registration number: Mandatory if you are registered. Clients who are also VAT-registered need your number to reclaim input tax. Omitting it on a VAT invoice makes the invoice technically invalid in the UK and EU.

Client Information

The invoice must clearly address the entity being billed:

• Client business name or full name: Use the exact legal name. "Smith Design Ltd" is not the same entity as "Smith Design" for legal and accounting purposes.
• Client billing address: The address associated with the client's payment function (which may differ from their trading address).
• Client contact name: The specific person or department responsible for approving and processing payments. "Accounts Payable", "Finance Department", or a named individual all help route the invoice correctly.
• Client email address: Where you are sending the invoice and where correspondence about payment will be directed.

Invoice Details

These administrative fields are essential for both parties' record-keeping:

• The word "Invoice": Sounds obvious, but always include it as a prominent heading. It distinguishes an invoice from a quote, estimate, receipt, or statement.
• Invoice number: A unique sequential identifier. See our article on invoice numbering systems for format recommendations.
• Invoice date: The date the invoice was issued. This is the start date for calculating the due date and for the client's accounts payable records.
• Supply date (or service date): The date the goods were delivered or the service was performed. In the UK and EU, this is a legally required field on VAT invoices and may differ from the invoice date.
• Purchase order number: If the client issued a purchase order (PO) for the work, include the PO number. This is essential for enterprise clients whose accounts payable systems require PO matching before authorising payment.

Itemised Line Items

The body of the invoice should contain a table with a row for each distinct service or product. Each row must include:

• Description: A clear, specific description of the work performed. "Web development — June 2024" is better than "services". "SEO copywriting — 5 × product page descriptions" is better than "writing".
• Quantity: Number of units, hours, days, or items. Always specify the unit type (hours, days, items).
• Unit rate: Price per unit (hourly rate, daily rate, per-item price).
• Line total: Quantity × unit rate. Always show the calculation even when it is simple — it makes the invoice easier to audit.

If the project was billed as a flat fee rather than time-based, use a quantity of 1 and state the full project fee as the unit rate, with a detailed description of the scope of work.

Tax Breakdown

Tax presentation must be transparent and accurate:

• Subtotal: The sum of all line item totals before tax. Always show this separately from the tax amount and total.
• Tax rate and amount: Show the applicable tax rate (e.g., "VAT 20%") and the calculated tax amount as a separate line. If multiple rates apply to different items, show each rate and amount separately.
• Total (including tax): The final amount the client owes. This should be the most prominent figure on the invoice.

If you are not registered for VAT/GST and no tax applies, you can omit the tax section — but in some jurisdictions you should add a note such as "VAT not applicable — below registration threshold" to avoid confusion.

Payment Information

This is the information the client needs to actually pay you. Incomplete payment information is one of the leading causes of invoice processing delays:

• Bank transfer details: Account holder name, bank name, sort code and account number (UK), IBAN and BIC/SWIFT (international). Include all fields — an IBAN without a BIC will fail for many international transfers.
• PayPal email address: If you accept PayPal. Specify whether you accept PayPal Friends & Family (no fee) or Goods & Services (buyer protection, but PayPal takes a fee).
• Other payment methods: Any other methods you accept, with the relevant details.
• Currency: Always specify the currency, especially for international invoices. "£1,200" and "$1,200" are very different amounts.

Payment Terms and Late Fees

Clear payment terms remove ambiguity and give you legal standing if you need to enforce payment:

• Payment due date: State both the payment terms (Net 30, Net 15) and the specific calendar due date (e.g., "Payment due: 15 September 2024"). Never rely on the client to calculate the due date.
• Late payment interest: If you charge interest on overdue invoices, state the rate and basis on the invoice. In the UK, the Late Payment of Commercial Debts (Interest) Act 1998 sets the statutory rate at 8% above the Bank of England base rate for B2B debts.
• Late fee policy: Some businesses prefer a flat late fee (e.g., £25 after 7 days overdue) rather than interest. Whatever your policy, it must be stated on the invoice to be enforceable.

Optional But Recommended Fields

• Notes section: A brief thank-you message, project reference details, or specific instructions for the accounts payable team. "Thank you for your business. Please reference invoice number INV-2024-042 with your payment."
• Your logo: A logo makes the invoice look professional and reinforces your brand identity. It also makes your invoices easier for clients to identify in their email inbox.
• Contract or agreement reference: If the invoice relates to a specific signed contract or statement of work, reference it by name or number.
• Delivery address (for physical goods): If different from the billing address.