Keep it short. Say what the invoice is for, the amount, the due date and how to pay, then attach it. Put the invoice number in the subject line. Thank them. Nothing else needs saying.
| Question | Short answer |
|---|---|
| Subject | Invoice number, what it is for, due date |
| Body | Amount, due date, how to pay, thanks: 3 to 5 lines |
| Attach | The invoice, usually as a PDF |
12 emails you can copy
Twelve emails to send with an invoice, for freelancers and small businesses. Each has a subject line you can use. Replace every [BRACKET] with a real fact.
Jump to: The plain versionDifferent jobsTerms, accounts and corrections
- The plain versionSubject: Invoice [NUMBER] for [PROJECT], due [DATE]Hello [CLIENT FIRST NAME], please find attached invoice [NUMBER] for [WORK], [AMOUNT]. Payment is due by [DATE]. You can pay by [METHOD AND DETAILS]. Thank you. [YOUR NAME]
- Very shortSubject: Invoice [NUMBER], due [DATE]Hello [NAME], invoice [NUMBER] is attached: [AMOUNT], due [DATE]. Thank you. [YOUR NAME]
- With the payment details in the emailSubject: Invoice [NUMBER] for [PROJECT]Hello [NAME], invoice [NUMBER] for [AMOUNT] is attached, due [DATE]. To pay: [ACCOUNT NAME, ACCOUNT DETAILS]. Please use [REFERENCE] as the payment reference. Thank you. [YOUR NAME]
More examples, by situation
Different jobs
- A finished projectSubject: Invoice [NUMBER] for [PROJECT]Hello [NAME], thank you for [PROJECT]. Invoice [NUMBER] for [AMOUNT] is attached, due [DATE]. I enjoyed working on it. [YOUR NAME]
- A monthly retainerSubject: Invoice [NUMBER] for [MONTH]Hello [NAME], invoice [NUMBER] for [MONTH] is attached: [AMOUNT], due [DATE]. It covers [WHAT, FOR EXAMPLE, THE AGREED [HOURS] HOURS]. [YOUR NAME]
- A stage paymentSubject: Invoice [NUMBER], stage [NUMBER] of [PROJECT]Hello [NAME], this is invoice [NUMBER] for the [FIRST / SECOND] stage of [PROJECT]: [AMOUNT], due [DATE]. The remaining [AMOUNT] is invoiced when [MILESTONE].
- A deposit invoiceSubject: Deposit invoice [NUMBER] for [PROJECT]Hello [NAME], the deposit invoice is attached: [AMOUNT], due [DATE]. I start on [START DATE] once it has reached me.
- Hours and expensesSubject: Invoice [NUMBER] for [PROJECT]Hello [NAME], the invoice covers [HOURS] hours at [RATE] and expenses of [AMOUNT]. The receipts are attached. Total: [TOTAL], due [DATE].
Terms, accounts and corrections
- Payment terms in the emailPayment terms are [NUMBER] days from the invoice date, as agreed on [DATE] in [QUOTE OR CONTRACT]. [ADD IF TRUE: LATE INVOICES CARRY INTEREST AS SET OUT IN THE AGREEMENT.]
- A new client's first invoiceAs this is our first invoice, here is how it works: [HOW TO PAY]. If your accounts team needs a purchase order number or anything else on the invoice, tell me and I will reissue it.
- Sending to accountsHello [ACCOUNTS NAME], [CLIENT FIRST NAME] asked me to send this invoice to you. It is for [WORK]. [ADD IF TRUE: PURCHASE ORDER NUMBER: [NUMBER].] Please tell me if you need anything else.
- A corrected invoiceSubject: Corrected invoice [NEW NUMBER], replaces [OLD NUMBER]Please ignore invoice [OLD NUMBER]. The attached invoice [NEW NUMBER] replaces it because [WHAT WAS WRONG]. The amount is now [AMOUNT]. Sorry for the mix-up.
Download these examples
The same text as this page, in one file, with the gaps ready to fill in.
What to avoid
- A long story. The invoice is the message.
- No due date, or "soon". Write the date.
- Bank details in a public place. Send them in the email or on the invoice only.
- Sending without checking the totals. A wrong invoice delays payment.
- Sending it to the wrong person. Ask who pays invoices.
Official pages. Rules differ by country. Not legal advice: check the rules that apply to you.
- GOV.UK: Late commercial payments: when a payment becomes late. It says: "If you do not agree a payment date, the law says the payment is late 30 days after either: the customer gets the invoice; you deliver the goods or provide the service (if this is later)." Read 5 October 2026.
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Check it before you send
Both are free.
Invoice Checker
What you give it: An invoice, yours or one you received, as text. It cannot read a picture or a scan.
What you get: Every line, the subtotal, the discount, the tax and the total worked out again, and every difference listed. It lists common fields that are missing and flags date, currency and rounding problems. No tax advice. Without a code tool it shows the sums by hand and says they need checking.
Late Payment Chaser (UK)
What you give it: The unpaid amount, the invoice date, and the due date if you agreed one.
What you get: What you can claim under UK late-payment law, worked out with a script and shown with official sources, and three reminder emails to send. UK business-to-business debts only. Not legal advice.
Free. It also works as a paste-in text in a chatbot; there the assistant does the arithmetic, so check its working.
What should I write in an email with an invoice?
Say what the invoice is for, the amount, the due date and how to pay. Attach the invoice and say thank you. Three to five lines is enough.
What should the subject line be?
The invoice number, what it is for and the due date, so the client can find it later: "Invoice [NUMBER] for [PROJECT], due [DATE]".
When should I send an invoice?
As soon as the work is done or the stage is reached, unless your agreement says otherwise. For UK business customers with no agreed date, GOV.UK says payment is late 30 days after the customer gets the invoice or after you deliver, if that is later. So the day you send it matters.
Should I attach the invoice as a PDF?
A PDF is the usual choice, because it looks the same on every device. Check that the client does not need another format.
Questions people ask
What do I do with the [BRACKETS]?
Replace each one with a real fact. If you cannot, delete the line. Never leave a bracket in what you send.
Is this legal advice?
Not legal advice. For a large debt, a dispute or court, get advice.
More
Sources
- Late commercial payments: when a payment becomes late, read 5 October 2026