How to Send an Invoice by Email (Templates and Best Practices)
The right email gets your invoice paid faster. Here's exactly what to write when sending an invoice by email, with subject line templates, body copy, and common mistakes to avoid.
Why the email matters as much as the invoice
A well-formatted PDF invoice is useless if the email around it is confusing. Accounts-payable teams process dozens of invoices a day, and they prioritize the ones that are easy to identify, easy to open, and easy to route for approval. A vague subject line or a missing invoice number can add days to your payment time.
The goal of the email is simple: make it immediately clear who it's from, what it's for, how much is owed, when it's due, and how to pay. Everything else is noise.
The perfect invoice email subject line
The subject line should contain the word 'Invoice', your invoice number, your business name, and the client name or project. This makes the email instantly searchable and identifiable. Examples:
- Invoice INV-2026-0042 from Amison Design — Acme Website Redesign
- Invoice #0015 — Sarah Johnson Photography — Wedding Deposit
- Invoice INV-089 from Northside Plumbing — Kitchen Refit Phase 2
What to include in the email body
Keep the email body short and professional. Include these elements in order:
- A greeting using the client's name (or the accounts-payable contact if different from your main contact).
- One sentence stating what the invoice is for — reference the project or work completed.
- The total amount due and the due date.
- How to pay — mention the payment method and where to find payment details (on the invoice).
- A note that the invoice PDF is attached (or a share link if you're using one).
- A professional sign-off with your name, business name, and contact details.
Sample invoice email template
Here's a template you can adapt for any client. Copy the structure and swap in your details:
- Subject: Invoice INV-2026-0042 from [Your Business] — [Project Name]
- Hi [Client First Name],
- Please find attached invoice INV-2026-0042 for [project or work description].
- Amount due: $[total] (including [tax rate]% [VAT/GST/sales tax])
- Due date: [due date]
- Payment details are on the invoice. If you have any questions about the billing, just reply to this email.
- Thanks for the work — looking forward to the next one.
- Best regards,
- [Your Name]
- [Your Business]
- [Phone] | [Email]
Attachment vs shareable link
Attaching the PDF is the traditional approach and works fine for most clients. However, a shareable link has two advantages: the client can open it instantly without downloading anything (less friction = faster payment), and you can see whether it's been opened. Our invoice generator creates a share link in one click — paste it into the email instead of (or alongside) the attachment.
If you do attach a PDF, make sure the filename is professional and identifiable — 'INV-2026-0042-Amison-Design.pdf' is far better than 'invoice.pdf'.
Common mistakes that delay payment
These are the email mistakes that most commonly cause slow payment:
- Vague subject line — 'Invoice' alone isn't enough; include the number and project.
- Missing invoice number in the email — the AP team needs it to match your invoice to their system.
- Sending to the wrong person — if your main contact isn't the one who pays, ask for the billing contact and address the email to both.
- Not stating the due date explicitly — don't make the client calculate it from payment terms.
- Forgetting to attach the PDF — it happens more than you'd think. Double-check before sending.
Following up on an unpaid invoice email
If the due date passes without payment, send a polite reminder. Reference the original invoice number and due date, restate the amount, and ask if there's anything they need from you to process it. A friendly tone gets better results than a demanding one — most late payments are administrative delays, not intentional. Our invoice generator's share links let you see if the client has opened the invoice, which helps you time your follow-up.
Frequently Asked Questions
Ideally both. CC your main contact (so they know the invoice was sent and can nudge their finance team) and address it to the billing or AP contact if you have their email. If you don't know who handles payments, ask your main contact — 'Who should I send invoices to?' is a normal question.
No — shareable invoice links are increasingly common and many clients prefer them because they open instantly on any device. Include both a link and a PDF attachment if you're unsure. The link also lets you track whether the client has viewed the invoice.