How to Write a Professional Invoice Email (With Templates)

Sending an invoice is the last step between completing work and getting paid — yet most freelancers and small business owners treat the accompanying email as an afterthought. A poorly worded invoice email can delay payment, create confusion, or make you look less professional than the work you've just delivered.

This guide covers exactly what to include in an invoice email, how to adjust your tone for different situations, and gives you ready-to-use templates for every scenario you're likely to encounter.

Why the invoice email matters

Your invoice email is often the last direct communication before money changes hands. It sets the tone for how the payment is received and processed. A clear, professional email:

1. Gets your invoice to the right person quickly — sometimes the client forwards it directly to their finance team
2. Reduces back-and-forth by anticipating common questions (what's it for, which bank details, what are the terms)
3. Creates a written record of when the invoice was sent and to whom
4. Positions you as a professional, which makes clients more likely to prioritise your payment

What every invoice email should include

1. A clear subject line that references the invoice number and amount — finance teams process dozens of emails and a vague subject line means your invoice gets buried
2. A brief, friendly opening — one sentence thanking them for the work or referencing the project
3. The key invoice details in the body — invoice number, amount, and due date — so the reader doesn't have to open the attachment to know what it's about
4. The invoice as an attachment — always PDF, never an editable format
5. Your payment details — include sort code and account number in the email body as well as on the invoice itself, so they're visible without opening the attachment
6. A clear call to action — tell them what you want them to do ("please arrange payment by [date]")
7. An offer to help — "please let me know if you have any queries" reduces friction and shows goodwill

Template 1: Standard invoice email

Use this for regular clients and straightforward project invoices. Keep it brief — they know who you are and what the work was.

Subject: Invoice INV-2026-0047 — £[amount] — [Your business name]

Hi [Name],

Please find attached invoice INV-2026-0047 for £[amount] (including VAT), due for payment by [date].

This covers [brief description of work — e.g. "website design for the Hartley project, completed January 2026"].

Payment details:

Account name: [Your business name]

Sort code: XX-XX-XX

Account number: XXXXXXXX

Reference: INV-2026-0047

Please let me know if you have any questions. I look forward to receiving payment by [date].

Many thanks,

[Your name]

Template 2: First invoice to a new client

When invoicing a client for the first time, add a little more context. They may not have your bank details saved, and their finance team will be processing you as a new supplier for the first time.

Subject: Invoice INV-2026-0047 — £[amount] — [Your business name]

Hi [Name],

It was great working with you on [project name]. Please find attached my invoice for the work completed — invoice INV-2026-0047 for £[amount] including VAT, with payment due by [date].

As this is our first invoice, I've included my full payment details below. If your finance team needs any additional information — a purchase order number, a supplier form, or a copy of my VAT registration — please just let me know and I'll get it over to you straight away.

Payment details:

Account name: [Your business name]

Sort code: XX-XX-XX

Account number: XXXXXXXX

Reference: INV-2026-0047

Please don't hesitate to get in touch if you have any queries about the invoice. Looking forward to working together again.

Best regards,

[Your name]

Template 3: Invoice for a retainer or recurring work

For monthly retainers or ongoing work, keep the email short — your client is expecting it and knows the context. Just make sure the period is clearly referenced so their accounts team can match it easily.

Subject: Invoice INV-2026-0047 — [Month] retainer — £[amount]

Hi [Name],

Please find attached my invoice for [Month]'s retainer — INV-2026-0047 for £[amount] including VAT, due by [date].

Payment details as usual:

Sort code: XX-XX-XX · Account: XXXXXXXX · Ref: INV-2026-0047

Thanks as always — let me know if anything looks off.

[Your name]

Template 4: Invoice sent to a finance team (not your main contact)

Many larger businesses require invoices to be sent directly to an accounts payable address rather than your day-to-day contact. This template is for when you're emailing someone you've never spoken to, CC'ing your main contact.

Subject: Invoice INV-2026-0047 — [Your business name] — £[amount] — due [date]

Dear [Finance team / Accounts Payable / Name if known],

Please find attached invoice INV-2026-0047 from [Your business name] for £[amount] including VAT at 20%, due for payment by [date].

This invoice relates to [brief description of work] provided to [client company name] during [period]. I have CC'd [your main contact name] for reference.

Payment details:

Account name: [Your business name]

Sort code: XX-XX-XX

Account number: XXXXXXXX

Reference: INV-2026-0047

Please do not hesitate to contact me if you require any further information to process this payment.

Yours sincerely,

[Your name]

[Your business name]

[Phone number]

Template 5: Invoice with a purchase order number

Some larger clients won't process an invoice without a purchase order (PO) number. Always reference the PO number in the subject line and email body — it's the key piece of information their finance system needs to match and approve the invoice.

Subject: Invoice INV-2026-0047 — PO [number] — £[amount] — [Your business name]

Hi [Name],

Please find attached invoice INV-2026-0047 for £[amount] including VAT, referencing purchase order [PO number]. Payment is due by [date].

This covers [brief description of work].

Payment details:

Account name: [Your business name]

Sort code: XX-XX-XX

Account number: XXXXXXXX

Reference: PO [number] / INV-2026-0047

Please let me know if any additional information is needed. Happy to provide a signed delivery note or timesheet if required.

Many thanks,

[Your name]

Common invoice email mistakes to avoid

Vague subject lines

Subjects like "Invoice attached" or "Please see attached" give finance teams nothing to work with. Always include the invoice number, your business name, and ideally the amount. A finance team processing 200 emails a day needs to identify your invoice at a glance.

Sending as a Word document or editable file

Always send invoices as PDFs. Word documents can be accidentally edited, may not display correctly on all devices, and look less professional. PDF preserves your formatting exactly as intended.

Not including payment details in the email body

Many clients pay directly from their email without opening the attachment. If your bank details aren't in the email body, you're adding an unnecessary step between them and paying you.

Forgetting to actually attach the invoice

It happens to everyone — but it delays payment and is easily avoided. Using invoicing software that attaches the PDF automatically removes this risk entirely.

Using an unclear or generic email address

Sending invoices from a personal Gmail or a vague address like info@yourdomain.com can trigger spam filters or create confusion. Use a consistent, professional address — ideally invoices@yourdomain.com or accounts@yourdomain.com — and use it every time.

Not stating the due date

Including the invoice is not enough — state the due date clearly in the email body. "Payment due 30 days from invoice date" leaves room for confusion. "Payment due by 14 February 2026" does not.

Adjusting your tone for the situation

Send invoice emails automatically with Invoice Kwik

Invoice Kwik sends a professional invoice email automatically every time you create an invoice — with your payment details, the PDF attached, and the due date clearly stated. You can customise the email template once and it applies to every invoice you send from that point on.

Just say or type "Invoice ACME Ltd £1,500 for consulting" and the invoice is created, the email is written, and it's ready to send in under 30 seconds. No copying and pasting bank details, no forgetting to attach the PDF.

Try Invoice Kwik free — no credit card required.