How to Email an Invoice to a Client: Best Practices + 5 Templates

An invoice email is a professional communication, not an afterthought. Get it right and you get paid faster. Get it wrong and your invoice sits in a spam folder for three weeks. Here's everything you need — including 5 ready-to-copy templates.

The anatomy of a professional invoice email

Subject line

Easy to find, filters correctly, AP can act without opening

Must include: Invoice number, project/your name, due date

e.g. "Invoice #042 — Website Redesign — Due 29 May 2026"

Greeting

Personalization increases open and response rates

Must include: Professional but warm — use their name

e.g. "Hi Sarah,"

Body — one sentence context

Context before the ask — never just say 'Invoice attached'

Must include: What the invoice is for

e.g. "Please find attached Invoice #042 for the website redesign project."

Payment details

All info needed to pay, in the email body — not just on the PDF

Must include: Amount, due date, how to pay

e.g. "€2,400 due by 29 May. Bank transfer to IBAN [X] or pay online: [link]"

Attachment

PDF is professional and uneditable. Named file is easy to file.

Must include: PDF invoice — named clearly

e.g. "Invoice-042-YourName.pdf"

Sign-off

Ends on a friendly note, reduces friction for the client

Must include: Brief, professional, open door for questions

e.g. "Let me know if you have any questions. Best, [Name]"

5 invoice email templates (copy-paste ready)

Standard new invoice

Subject:

Invoice #[N] — [Project Name] — Due [Date]

Body:

Hi [Client Name],

Please find attached Invoice #[N] for [brief description of work], totalling [amount].

Payment is due by [due date]. You can pay via:
• Bank transfer: [your bank details]
• Online: [payment link]

Let me know if you have any questions about this invoice.

Best,
[Your Name]

First time sending to this client

Subject:

Invoice #001 — [Your Name / Company] — [Project] — Due [Date]

Body:

Hi [Client Name],

It's been great working with you on [project]. As agreed, please find attached Invoice #001 for [amount].

A couple of payment details:
• Due date: [date]
• Bank: [account details] 
• Reference: please use invoice number #001

I've also included a payment link if that's easier: [link]

Looking forward to working with you again.

[Your Name]

Project completion invoice

Subject:

Final Invoice #[N] — [Project Name] — Project Complete 🎉

Body:

Hi [Client Name],

[Project name] is now complete! All deliverables have been handed over as agreed.

Attached is the final invoice #[N] for [amount] (the final [X]% milestone).

Summary of what was delivered:
• [Deliverable 1]
• [Deliverable 2]
• [Deliverable 3]

Payment of [amount] is due by [date].

Thank you for a great project — I hope we get to work together again soon.

[Your Name]

Monthly retainer invoice

Subject:

Monthly Invoice #[N] — [Month Year] — [Your Name]

Body:

Hi [Client Name],

Attached is your monthly invoice #[N] for [Month] [Year] services, totalling [amount].

Services covered this month:
• [Service/deliverable 1]
• [Service/deliverable 2]
• [Hours worked: X hrs @ €Y/hr] (if applicable)

As always, payment is due within [X] days. Bank details and payment link are on the invoice.

[Your Name]

International client invoice

Subject:

Invoice #[N] — [Project] — [Amount] [Currency] — Due [Date]

Body:

Dear [Client Name],

Please find attached Invoice #[N] for [project], totalling [amount in their currency] / [amount in your currency].

Important payment details:
• Currency: [currency] — amount is [X]
• IBAN / SWIFT: [your international banking details]
• Reference: Invoice #[N]
• Due date: [date]

Please note: any bank transfer fees are the responsibility of the sender. If there is a shortfall due to transfer fees, I will follow up.

Payment link (card): [link]

Thank you,
[Your Name]

The 3 most common invoice email mistakes

❌

Vague or missing subject line

Impact: Invoice gets lost, sorted to the wrong folder, or ignored

✅ Fix: Always use: Invoice #[N] — [Context] — Due [Date]

❌

Forgetting the PDF attachment

Impact: Client can't pay even if they want to — you need to follow up again

✅ Fix: Attach the PDF FIRST, then write the email. Never the other way around.

❌

No payment link or bank details in the email body

Impact: Client has to open PDF, find details, copy them manually — friction = delay

✅ Fix: Include payment link or bank details in the email body AND the invoice PDF

When to send your invoice email

✅ Best times

  • Monday–Wednesday
  • 9am–11am (client's timezone)
  • Immediately after project completion
  • Same day as milestone delivery

❌ Avoid

  • Friday afternoon
  • Public holidays
  • End of their financial quarter
  • Monday before 9am

Pro tip:For larger invoices (€1,000+), send a heads-up message on WhatsApp, Slack, or phone immediately after emailing: "Just sent over Invoice #[N] — let me know if you have any questions." This one step can cut payment time by days.

Automating invoice emails with Chaser

Manually sending invoice reminder emails is time-consuming and emotionally draining. Chaser automates your entire follow-up sequence:

  • →Day 3 after due: Friendly reminder — "just checking in"
  • →Day 7: Polite follow-up — notes it's now overdue
  • →Day 14: Firm notice — payment urgently requested
  • →Day 30: Final demand — before escalation to collections
Automate Invoice Emails with Chaser →

Frequently Asked Questions

What is the best subject line for an invoice email?

The best invoice email subject line is clear and contains all the key info: 'Invoice #[N] — [Project/Your Name] — Due [Date]'. This lets the client find it easily, understand what it's for without opening it, and your accounts payable contact can process it immediately. Never use vague subjects like 'Payment' or 'Work complete' — they get lost or spam-filtered.

Should I attach the invoice as PDF or just send a link?

PDF attachment is standard and expected by most accounting departments. Always attach the PDF. You can also include a payment link in the email body — many clients find it easier to pay by clicking a link than by processing a bank transfer. For best results: attach PDF + include payment link in the body.

When is the best time to send an invoice?

Monday to Wednesday, 9–11am, is optimal — you catch accounts payable staff at the start of the week before they get buried. Avoid Friday afternoons (gets buried over the weekend) and Monday mornings before 9am. For international clients, send during their business hours, not yours.

Should I follow up immediately after sending?

Yes, for new clients or large invoices: send a brief message on the channel you communicate most (WhatsApp, Slack, etc.): 'Just sent over invoice #123 — let me know if you have any questions.' This ensures they received it and opens a dialogue. Don't do this for every regular invoice with established clients — it becomes annoying.

How do I email an invoice if I forget to attach it?

We've all done it. Just send a follow-up immediately: 'Apologies — I forgot the attachment! Here's invoice #[N]: [attach].' Don't overthink it. One thing you can do to prevent this: never write the email before attaching the file — attach first, write after.

Can I automate invoice emails?

Yes, and you should. Chaser automates your entire invoice email sequence — the initial send plus up to 4 follow-up reminders if the invoice goes unpaid. Each email escalates in firmness: friendly reminder → polite follow-up → firm notice → final demand. You set it up once; Chaser handles the rest.