How to Send an Invoice by Email (With Templates & Wording)

To send an invoice by email, attach the invoice as a PDF, write a clear subject line that includes the invoice number and your business name (for example, Invoice INV-1042 from Maple Studio — due 14 July), and keep the body short: confirm the work, state the amount due and due date, say how to pay, and thank them. That's the whole job — the rest of this guide gives you the exact wording, subject lines, and copy-paste templates for the first send, a polite reminder, and a thank-you.

You already did the hard part by creating the invoice. A well-written email is what actually gets it paid — a vague message buries your request, while a clear one tells the client exactly what to do in ten seconds. Below is everything that goes into a professional invoice email, why each piece matters, and ready-to-use templates you can adapt today.

What to write when sending an invoice (the 6 essentials)

A good invoice email is short. The PDF carries the detail; the email just frames it and points the reader to the next step. Every invoice email should contain these six things:

1. A brief greeting using the client's name — "Hi Sarah," reads far better than "To whom it may concern."
2. One line confirming the work or order so the client instantly remembers what they're paying for ("for the website redesign we completed last week").
3. The invoice number — this lets both of you reference it in future emails and matches it to their records.
4. The amount due and the due date, stated in plain words in the body, not hidden only inside the attachment.
5. How to pay — bank details, a payment link, or whatever method you accept, so there's zero friction.
6. A short thank-you and your sign-off with your name and business so it reads as a real person, not a system.

Then attach the invoice itself. Keep the body to four or five lines; the easier it is to read on a phone, the faster you get paid. If you're still deciding what belongs on the invoice document (versus the email), our guide on how to invoice a client walks through the full document, line by line.

The single biggest mistake is making the client hunt for the number. If the amount and the "pay here" step aren't visible without opening the attachment, you've added a step — and every extra step is a reason to deal with it later.

Invoice email subject lines that get opened

The subject line decides whether your email gets actioned now or lost in a busy inbox. A strong invoice subject line is specific and searchable: it names the invoice, says who it's from, and ideally signals the due date. Months later, "invoice" alone is impossible to find — but a number and a name are searchable in one keystroke.

Use a format like one of these:

• Invoice INV-1042 from [Your Business] — due 14 July
• Invoice #1042 for [Project name] — [Your Business]
• [Your Business] invoice INV-1042 — $1,250 due 14 July

Avoid vague subjects like "Hello", "Following up", or a bare "Invoice", and skip ALL-CAPS or urgency words on a first send — they read as spam and can hurt deliverability. If you number your invoices in a consistent sequence (and you should), our note on how to generate an invoice number explains a simple, professional scheme that makes these subject lines effortless.

PDF attachment vs payment link: which to use

This is the question most people get stuck on. The honest answer is that they solve different problems, so the best invoice emails use both.

Attach a PDF (the safe default)

A PDF is the professional standard for one simple reason: it looks the same everywhere. It opens on any phone, laptop, or accounting system, it can't be accidentally edited, and the client can save it, print it, or forward it to their bookkeeper or finance team without anything breaking. If you only do one thing, attach a PDF. You can build and download a clean one in seconds with the PDF invoice generator.

Add a payment link (the speed boost)

A "Pay now" link in the body removes friction — the client clicks, pays, done. This is where you'll often see the fastest settlement, because the client never has to copy bank details or log in elsewhere. The trade-off is that links depend on a payment provider, may carry processing fees, and can occasionally trip a cautious client's spam filter.

The strongest approach: attach the PDF and include a payment link or your bank details in the body. The PDF reassures and records; the link makes paying instant. Whatever you choose, make sure the payment method also appears inside the invoice document itself so it survives if the email body is skimmed or forwarded.

How to send an invoice on Gmail (step by step)

You don't need special software — your normal inbox is fine. The steps are the same in Gmail, Outlook, or Apple Mail; here's the Gmail flow:

1. Create and download the invoice as a PDF. If you haven't made it yet, the free invoice generator lets you fill it in and download a PDF with no sign-up. Our guide to creating an invoice covers the fields if you're starting from scratch.
2. Open Gmail and click Compose. Put the client's email in the "To" field. If a colleague or your own accounts address needs a copy, add it in BCC, not To — clients don't need to see who else is on the thread.
3. Write a specific subject line using one of the formats above, with the invoice number and your business name.
4. Paste your email body(use a template below) and fill in the bracketed details — name, invoice number, amount, due date, and how to pay.
5. Attach the PDF. Click the paperclip icon, select your invoice file, and confirm it appears before sending. Name the file clearly, such as Invoice-INV-1042-MapleStudio.pdf, so it's obvious in the client's downloads folder.
6. Send to yourself first if it's a big or new client. A quick test send confirms the attachment opens and the formatting looks right before it reaches the client.

A practical tip: save your best template as a Gmail "template" (Settings → Advanced → Templates, then compose and save) so the next invoice is a two-minute job instead of a rewrite.

Copy-paste invoice email templates

Use these as starting points and swap the bracketed parts. They're deliberately short — that's what makes them work.

1. First invoice email (the send)

Subject: Invoice INV-1042 from [Your Business] — due 14 July

Hi [Client name],

Thank you for working with us on [project / order]. Please find invoice INV-1042 attached as a PDF.

Amount due: $1,250
Due date: 14 July 2026
Pay by: [bank transfer details / payment link]

If anything looks off or you have any questions, just reply to this email and I'll sort it out. Thanks again — it's been a pleasure.

Best,
[Your name], [Your Business]

2. Polite payment reminder (a few days after the due date)

Send this when an invoice has just slipped past its due date. Keep it warm and assume the best — most late payments are simple oversights, not refusals.

Subject: Reminder: invoice INV-1042 from [Your Business] — due 14 July

Hi [Client name],

Just a friendly reminder that invoice INV-1042 for $1,250 was due on 14 July. I've attached it again here for convenience.

If it's already on its way, thank you — please ignore this. If not, you can pay by [link / bank transfer], and do let me know if you need anything from me to process it.

Thanks,
[Your name], [Your Business]

That's the gentle first nudge. If a client keeps going quiet or the invoice ages further, you'll need a firmer escalation sequence — the full set of follow-up templates, timing, and when to mention late fees lives in our guide on how to chase unpaid invoices. Any late-fee percentage or interest you charge should be agreed in your terms up front and stays within what's allowed where you operate, as the limits vary by country and state.

3. Thank-you follow-up (after payment lands)

This one is optional but punches above its weight — it closes the loop, confirms the payment was received, and quietly sets up repeat work.

Subject: Payment received — thank you (invoice INV-1042)

Hi [Client name],

Confirming that your payment for invoice INV-1042 came through — thank you. It was great working with you on [project], and I'd be glad to help again whenever you need.

Wishing you all the best,
[Your name], [Your Business]

A worked example, start to finish

Imagine you're Maple Studio and you just finished a logo project for a client named Sarah. Here's the whole flow in practice:

• You create the invoice, number it INV-1042, set the total at $1,250, and a due date of 14 July, then download it as Invoice-INV-1042-MapleStudio.pdf.
• You open Gmail, address it to Sarah, and write the subject Invoice INV-1042 from Maple Studio — due 14 July.
• You paste the first-send template, fill in Sarah's name, the project ("the logo design"), the amount, the due date, and a payment link, then attach the PDF.
• Two days after 14 July, no payment has landed, so you send the polite reminder — same thread, attachment re-attached.
• Payment arrives the next morning. You send the short thank-you, and you're done with a happy client and a clean record.

That sequence — clear send, gentle reminder, warm thank-you — handles the vast majority of invoices without any awkwardness.

Quick mistakes to avoid

• Don't bury the ask. The amount, due date, and how to pay belong in the email body, not only in the attachment.
• Don't send a vague subject line."Invoice" alone is unsearchable; always include the number and your business name.
• Don't skip the PDF. Pasting figures into the body with no attachment looks informal and gives the client nothing to file.
• Don't forget your contact details. Make it effortless for the client to query or confirm by replying.
• Don't double-send by accident. Keep reminders on the same email thread so the history stays in one place.

Keep good copies of everything you send, too — most businesses are expected to retain invoice records for several years, though the exact number of years varies by country, so check your local rules.

Frequently Asked Questions

What should I write in an email when sending an invoice?

A short greeting, one line confirming the work or order, the invoice number, the amount due and due date, how to pay, and a thank-you — and attach the invoice as a PDF so nothing is missing.

What is a good subject line for an invoice email?

Keep it clear and findable, for example: Invoice INV-1042 from [Your Business] — due 14 July. The invoice number, your name, and the due date make it easy to search and act on.

Should I attach a PDF or send a link?

A PDF attachment is the safe default — it always opens and looks the same on any device. A payment link in the body makes paying faster, so the strongest approach is to do both: attach the PDF and include a pay-now link.

How do I send an invoice for free?

Create the invoice with a free tool, download it as a PDF, and email it yourself from your normal inbox. You can build and download one in under a minute with the free invoice generator and pay nothing.