How to Write an Invoice (With Examples)

Writing a clear, professional invoice is the difference between getting paid in 7 days vs 60 days. This guide shows you exactly how to write an invoice that looks professional, meets legal requirements, and gets paid faster.

The 10 essential parts of an invoice

Every professional invoice needs these 10 elements:

  • Header with the word 'INVOICE' clearly visible
  • Your business name and contact details
  • Your logo (optional but recommended)
  • Unique invoice number
  • Issue date and due date
  • Client's billing details
  • Itemized line items with rates
  • Subtotal, tax, discount, total
  • Payment terms and instructions
  • Notes or thank-you message

How to word an invoice professionally

The tone should be polite but firm. Use clear, descriptive language for line items (e.g. 'Web design - homepage layout' instead of 'design work'). Specify quantities and rates clearly. Include payment terms in plain language: 'Payment due within 30 days of invoice date.'

Step-by-Step Guide

  1. 1

    Add a clear invoice header

    The word 'INVOICE' should be prominent at the top, along with your invoice number and date.

  2. 2

    Identify yourself and your client

    Both parties' full legal names, addresses, and contact details. Include tax IDs if required by your country.

  3. 3

    Describe what you're billing for

    Use clear descriptions. Instead of 'work', write 'Logo design - 3 concepts + 2 revisions'. The client should know exactly what they're paying for.

  4. 4

    Show the math

    List quantities, rates, subtotal, tax, discounts, and total. Make it easy to verify.

  5. 5

    Specify how and when to pay

    Include payment terms ('Net 30'), accepted methods (bank transfer, PayPal, etc.), and account details if needed.

Frequently Asked Questions

Should I include my SSN on invoices?
Avoid putting your SSN on invoices for security. Use an EIN instead (free from the IRS). For non-US, use your business tax registration number.
Can I write an invoice in Word or Excel?
Yes, but it's much faster to use a free invoice generator like InvoiceGen. You get pre-built templates, automatic calculations, and PDF download — no formatting headaches.