Guides

How to Write an Invoice Email (With Templates You Can Copy)

Getting paid on time starts before an invoice is ever late. The email you send with the invoice decides whether it gets paid in one click or sits in an inbox waiting for someone to work out what it is. A good invoice email is short, easy to find later, and makes paying the obvious next step. Here's what to include, subject lines that work, and templates you can copy for the most common situations.

What every invoice email needs

• A searchable subject line with the invoice number, so the client (or their accounts team) can find it again.
• The invoice number, the amount due and the due date, written in the body, not only in the attachment.
• One line on what the invoice covers, such as the project, milestone or billing period.
• The invoice itself, attached as a PDF or linked.
• A direct way to pay, ideally a payment link, plus any other accepted methods.
• Your payment terms, including any late fee the client already agreed to.
• A thank-you and an invitation to ask questions.

Keep the body to a few sentences. Detailed line items belong on the invoice, not in the email. The goal is that someone skimming on their phone knows what this is, how much, by when, and how to pay.

Subject lines that get invoices found and paid

• Invoice #[number] from [Your business name]: due [date]
• Invoice #[number] for [project name]
• [Month] invoice #[number]: [Your business name]
• Invoice #[number] (PO [PO number]) from [Your business name]

Avoid vague subjects like "Payment" or "Hi". If the client gave you a purchase order number, always include it, because many accounts teams can't process an invoice without one.

Before you hit send

• Send it to the person who actually pays invoices. Ask your contact who that is at the start of the project.
• Double-check the invoice number, amount, due date and that the attachment is really attached.
• Send it promptly, ideally the day the work or milestone is delivered, while the value is fresh.
• Send from a professional address the client recognizes, so the email isn't missed or filtered.

Template 1: Standard invoice email

Subject: Invoice #[number] from [Your business name]: due [due date]

Hi [Client name],

Thanks again for the opportunity to work on [project name]. Please find invoice #[number] for [amount] attached, covering [short description of the work].

Payment is due by [due date]. You can pay here: [payment link]
[Other accepted methods, if any]

If you have any questions about the invoice, just reply to this email.

Thanks,
[Your name]
[Your business name]

Template 2: First invoice to a new client

The first invoice sets expectations for every one after it, so it's worth restating your terms once, politely.

Subject: Invoice #[number] for [project name]

Hi [Client name],

It's been great working with you on [project name]. Attached is invoice #[number] for [amount], due on [due date].

A quick summary of my payment terms, as in our agreement:
- Invoices are due [30] days from the invoice date
- You can pay by [payment link / bank transfer / other]
- [Late fee terms, if your agreement includes them]

Could you confirm this is the right address for invoices, or let me know who I should send them to in future?

Thanks,
[Your name]

Template 3: Recurring or retainer invoice

Subject: [Month] invoice #[number]: [Your business name]

Hi [Client name],

Here's your [month] invoice #[number] for [amount], covering [retainer / services] for [billing period]. It's attached and due on [due date].

Pay here: [payment link]

Thanks as always,
[Your name]

Template 4: Milestone or deposit invoice

Subject: Invoice #[number]: [milestone name] for [project name]

Hi [Client name],

[Milestone name] is complete, and I've attached invoice #[number] for [amount] for this phase, as set out in our agreement.

Payment is due by [due date]: [payment link]

Once this is settled, I'll start on [next phase] as planned. Let me know if you have any questions about what's been delivered.

Thanks,
[Your name]

Template 5: Courtesy reminder before the due date

A friendly note a few days before the due date catches invoices that were never forwarded to the right person, and it doesn't feel like chasing because nothing is late yet.

Subject: Reminder: invoice #[number] due [due date]

Hi [Client name],

Just a friendly heads-up that invoice #[number] for [amount] is due on [due date]. I've attached it again for convenience.

Pay here: [payment link]

If it's already been scheduled, thank you, and please ignore this note.

Best,
[Your name]

Common mistakes that delay payment

• No due date, or "due on receipt" with no actual date the client can plan around.
• Leaving out the PO number or the client's internal reference.
• Sending it to your day-to-day contact, who forwards it days later, or never.
• Making the client hunt for how to pay, or offering only one awkward method.
• Burying the amount and due date inside the attachment.

Then follow up on schedule

Even a perfect invoice email gets missed sometimes. The fix is a consistent follow-up on the due date and shortly after, sent calmly every time. ChaseOwl does this for you, sending polite reminders automatically on the due date and at 3, 7 and 14 days late. You can try it free for up to 2 invoices, or see our late payment email templates for what to send once an invoice is overdue.

More guides

• How to Offer a Payment Plan for an Overdue Invoice (Email Templates)
• Net 30 Payment Reminder Schedule: When to Follow Up (With Templates)
• How to Charge Late Fees on an Invoice (Wording and Email Templates)

Free tools

• Late fee calculator: Enter the amount and due date to see days overdue and the late fee owed, as a flat fee or a monthly percentage.
• Payment reminder email generator: Write a friendly, firm or final reminder email for an unpaid invoice in seconds, ready to copy and send.
• Free invoice template: Fill in a clean invoice in your browser, then print it or save it as a PDF. No login needed.