What to Put on an Invoice (Free Checklist)

Short answer: A complete invoice includes your business name and contact details, the client’s details, a unique invoice number, the invoice and due dates, an itemized list of services with rates, the subtotal, any tax, the total amount due, and clear payment instructions. Missing any of these fields is the most common reason invoices get paid late. Use the free checklist below to make sure yours is complete every time.

An invoice is only useful if it contains everything the client needs to pay you without asking questions. A vague invoice creates back-and-forth emails and delays your money. This checklist works for freelancers and small businesses in the United States, Canada, the United Kingdom, and the EU, with notes on regional differences like VAT.

What is the essential invoice checklist?

Use this checklist for every invoice you send. If you can check all of these boxes, your invoice is professional and complete.

• The word “Invoice” clearly at the top
• Your business name (legal or trading name)
• Your contact details (email, phone, address)
• Your logo (optional, but looks professional)
• Client’s name and company
• Client’s billing address
• A unique invoice number (e.g., INV-0007)
• Invoice date (the date you issue it)
• Due date (or terms like “Net 30”)
• Itemized list of services or products
• Quantity, rate, and line total for each item
• Subtotal (before tax)
• Tax (sales tax, GST, or VAT, if applicable)
• Total amount due (in the correct currency)
• Payment methods (bank transfer, check, PayPal, etc.)
• Payment terms and any late-fee policy
• A thank-you or short note (optional, builds goodwill)

Why does each invoice field matter?

Every field on the checklist solves a specific problem. Here is what each one does.

Field	What it prevents
Invoice number	Lost or duplicated payments; messy records
Invoice and due dates	Confusion about when payment is expected
Itemized services	Disputes over what the charge covers
Rates and quantities	Arguments about how the total was calculated
Subtotal and tax	Errors in the amount owed and tax reporting
Total in correct currency	Underpayment or currency mix-ups
Payment methods	Delays because the client does not know how to pay
Payment terms	Late payment because no deadline was set

A key fact: the single most-forgotten field is the due date. An invoice without a deadline invites the client to pay “whenever,” which usually means late.

What details identify you and your client?

The top of the invoice must make it obvious who is billing whom. Include your business name, address, email, and phone. If you have a business tax identifier, list it where appropriate for your region.

For the client, include the company name, the specific billing contact if you know it, and the billing address. Sending an invoice to the wrong person or department is a common cause of delay, so confirm the correct recipient before you send.

Regional identifier notes:

• United States: You may include your EIN or note that a W-9 was provided; freelancers who earn $600 or more from a client may receive a Form 1099-NEC.
• United Kingdom: A sole trader includes their name and business address; VAT-registered businesses must include a VAT number.
• EU: VAT-registered sellers include their VAT identification number, and cross-border B2B invoices may fall under reverse-charge rules.

How should services be itemized on an invoice?

Itemizing means listing each piece of work separately with its own line. This transparency prevents disputes and makes the total easy to verify.

For each line item, include:

1. A clear description of the work (e.g., “Homepage copywriting, 800 words”).
2. The quantity or hours.
3. The rate (hourly rate or fixed price).
4. The line total for that item.

Separate different types of work. If you charged an hourly rate for research and a fixed fee for design, list them as two lines. This makes your invoice easy to read and signals professionalism.

How do taxes and totals appear on an invoice?

After the line items, show the math clearly so there is no ambiguity about the amount due.

• Subtotal: the sum of all line items before tax.
• Tax: any sales tax, GST, or VAT that applies, shown as its own line with the rate.
• Total due: the final amount, in the correct currency.

VAT note for the UK and EU: A proper VAT invoice must show the VAT rate applied, the VAT amount, and your VAT registration number. This lets VAT-registered clients reclaim the tax. Sole traders and small businesses below the VAT threshold do not charge VAT and should not add a VAT line.

US sales tax note: Whether you charge sales tax on services depends on the state. Many states do not tax professional services, but some do. Check your state’s rules or ask a tax professional.

What payment details should be on an invoice?

Make it effortless for the client to pay. List the payment methods you accept and include the exact details for each.

• Bank transfer: account name, account number, and routing/sort code or IBAN.
• Check: who to make it payable to and where to send it.
• Online options: PayPal address or other services you use.

Also restate your payment terms (for example, “Payment due within 14 days”) and any late-payment policy. Being explicit here is one of the most effective ways to get paid on time.

Build a complete invoice in under a minute with Keel

Remembering every field on this checklist is easier when your invoicing tool does it for you. Keel: Invoice Maker & Receipts by Ilura Technology builds a professional, complete invoice in under a minute, saves your business details so you never forget a field, exports a clean PDF you can send via the share sheet, and tracks what is still outstanding.

Keel keeps your data private: no bank connection, no cloud, and no account, so everything stays encrypted on your iPhone. It is free for up to 3 invoices per month with unlimited receipts and mileage. One honest note: Keel does not process online card payments in-app; it produces professional invoices and displays the payment options you choose.

Download Keel on the App Store: https://apps.apple.com/us/app/keel-invoice-maker-receipts/id6786659713

Frequently asked questions

What is the most important thing to include on an invoice? The amount due, a clear due date, and payment instructions are the three most critical items. Together they tell the client exactly what to pay, by when, and how.

Do I need an invoice number on every invoice? Yes. A unique invoice number keeps your records organized, prevents duplicate payments, and is expected for tax and accounting purposes. Sequential numbering like INV-0001 is the simplest system.

Should I put payment terms on an invoice? Yes. Stating terms such as “Net 15” or “Due on receipt” sets a clear deadline. Invoices without terms are far more likely to be paid late because the client has no set date.

Do freelancers need to add tax to invoices? It depends on your location and registration status. US freelancers may or may not charge sales tax depending on the state and service; UK and EU freelancers charge VAT only if they are VAT-registered.

Can I send an invoice as a PDF? Yes, and PDF is the recommended format. It looks identical on every device, cannot be edited by accident, and is accepted by virtually all clients and accounting systems.

This article is general information, not tax advice. Consult a qualified tax professional.