Writing an invoice is mostly about the words, not the layout. The numbers come from your agreement with the client; the wording decides whether someone who wasn’t in that conversation can approve the invoice without writing back to you.
A well-written invoice uses the client’s own names for things, describes each line specifically enough to recognize, states one clear due date and how to pay, and says nothing else. This guide shows how to write each part, with examples.
Write for the person who pays
The person who approves your invoice is often not the person you worked with. In a small business it may be the owner reading it on a phone between jobs; in a large company it is someone in accounts payable matching it against a purchase order. Neither of them knows the project.
So before you write anything, ask what that person needs to see to say yes:
- Who is this from, and is it a supplier we use?
- Which project, order or contract is it for?
- What exactly are we being charged for, and does it match what we agreed?
- How much, by when, and how do we pay?
Every line on the invoice should answer one of those questions.
Line item descriptions
Line items are where most invoices go wrong. A description should name the work or product, the quantity in units the client understands, and enough detail to match it to the agreement.
| Vague | Clear |
|---|---|
| Design work | Brand identity: wordmark, color and type system, two rounds of revisions |
| Labor | Cabinet installation and trim, 24 hours |
| Consulting | Operations review and analysis, September 1–15 |
| Materials | Quartz countertop, 32 sq ft |
| Website | Website design and build, six pages |
| Misc. | Travel to site, 42 miles at the IRS standard rate |
A few principles:
- Use the client’s vocabulary. If their purchase order says “Q3 catalog refresh”, use those words, not your internal project name.
- One line per thing they would recognize. Split work that was agreed separately; group small tasks that were not.
- Put detail on a second line. Many templates, including Folio’s, print a second line of a description in smaller type: the title on the first line, the deliverables beneath.
- Name the period for recurring work: “Monthly retainer — October”, “Weekly lawn care, 4 visits”.
Payment terms
Write the terms as a rule and a date. “Net 30” tells the client the rule; “Due November 30, 2026” tells them the date. Put both on the invoice.
Common terms:
| Term | Meaning |
|---|---|
| Due on receipt | Payable as soon as the invoice arrives |
| Net 7, Net 14, Net 30 | Payable within 7, 14 or 30 days of the invoice date |
| Net 30 EOM | Payable 30 days after the end of the month the invoice is dated |
| 50% deposit, balance on completion | Half before the work starts, the rest when it is finished |
If you charge a late fee, it must be one you agreed in advance, usually in your contract. State it plainly: “Payments received after the due date incur a fee of 1.5% per month, as agreed in our contract of June 4.”
Notes
The notes field is for anything the client needs that isn’t a charge. Keep it short; long notes don’t get read.
Good uses:
- A thank-you: “Thank you, Jo — a pleasure as always.”
- What happens on payment: “Final files are released on receipt of the balance.”
- A warranty: “One-year workmanship warranty from completion.”
- A reference: “Please quote INV-0042 with your payment.”
- The next step: “Next visit: Tuesday, November 3.”
Avoid repeating the terms in different words, apologizing for the amount, or adding conditions you never agreed.
Payment instructions
Write payment instructions as if the reader has never paid you before, because they may not have. Give the method, the account name, and every detail needed to complete it:
If you accept several methods, list them in order of preference. A payment link is fastest for clients who pay by card.
Tone
An invoice is a business document, not a letter. Be specific, polite and brief. There is no need to explain your prices or to soften the request; a clear invoice is itself a courtesy to the client. Save the warmth for the covering email and the one-line note.
The email that goes with it
Send the invoice as a PDF attached to a short email. The subject line should let the client find it later: Invoice INV-0042 from Marlow Studio — due November 30.
More on timing and follow-ups is in how to send an invoice.