How to Send an Invoice by Email (With Templates)

Most invoices are sent by email now. That's convenient, but it also means your invoice competes with everything else in the client's inbox. A clear email gets it opened, forwarded to the right person, and paid.

The checklist

Attach a PDF. Not a Word file, not an editable spreadsheet, not only a link.
Name the file clearly: Invoice-INV-0148-Harbor-Pine.pdf
Subject line with the invoice number and amount.
Say what it's for, how much, and when it's due in the first two lines.
Include payment details or a link, even though they're on the invoice.
Send it to whoever pays, and copy your contact if it's someone else.

Subject lines that work

Invoice INV-0148 from Northfield Studio: $2,400 due 30 Sept
Invoice INV-0148 for PO 4500123987
Northfield Studio invoice INV-0148 (August website work)

Avoid "Invoice" alone, "Here you go!" or anything that looks like spam or phishing.

Template: standard invoice email

Subject: Invoice INV-0148 from Northfield Studio: $2,400 due 30 September

Hi Sam,

Please find attached invoice INV-0148 for $2,400.00 for the website design work completed this month.

Payment is due by 30 September 2026. You can pay by bank transfer (details on the invoice) or by card here: [link]. Please use INV-0148 as the payment reference.

Thanks again, it was a great project to work on.

Best, Maya

Template: sending to an accounts payable inbox

Subject: Invoice INV-0148, PO 4500123987, Northfield Studio

Hello,

Attached is invoice INV-0148 for $2,400.00 against PO 4500123987, for website design services delivered to [contact name] in [department].

Due date: 30 September 2026. Bank details are on the invoice. Our vendor number is [number].

Please let me know if anything else is needed to process it.

Kind regards, Maya Ortiz, Northfield Studio

Template: first invoice to a new client

Subject: Invoice INV-0148: first invoice for [project]

Hi Sam,

Attached is the first invoice for [project]: the 50% deposit of $2,400.00, as agreed in the proposal.

It's due within 7 days (by 5 September). I'll start work as soon as it's received. Bank details are on the invoice, or you can pay by card here: [link].

If invoices should go to someone else in your team, just let me know and I'll send them there from now on.

Thanks, Maya

Who to send it to

Ask at the start of the relationship. Many companies want invoices sent to a dedicated AP address (like accounts@ or invoices@), and some upload them through a supplier portal. Your contact is often not the person who pays. Sending to the wrong place is one of the most common reasons invoices go unpaid.

When to send it

The day the work is delivered, or on your agreed billing day. Emails sent early on a weekday morning tend to get more attention than ones sent late on a Friday, but getting it out promptly matters much more than timing.

Why PDF

It looks the same on every device
It can't easily be edited by accident
Accounting systems and AP inboxes expect it
Some AP systems can automatically read PDF invoices; a Word document or image may not be processed at all

The PDFs from this site include a text layer, so they can be searched and read by accounts systems.

Download your invoice as a PDF named with the invoice number and client, ready to attach.

Open the invoice generator

After you send it

Note the send date in your invoice log.
Put the due date in your calendar.
If you haven't heard anything in a few days on a large invoice, it's fine to ask, "Can you confirm this reached the right person?"
If it passes the due date, use the payment reminder templates.

Watch out for invoice fraud

Invoices by email are a favourite target for scammers, who intercept or imitate them and change the bank details. Never change payment details by email alone, and warn your clients that you'll never do so either. See invoice fraud.