How to Send an Invoice by Email: 7 Templates That Get You Paid Faster
You did the work, you made the invoice — and now it sits in your drafts because you're not sure what to write in the email. Most freelancers either send the invoice with no message at all (cold, easy to ignore) or over-explain with three paragraphs of apology (undermines you). The email matters: it's the difference between an invoice that gets paid this week and one that sinks to the bottom of the inbox.
This guide covers exactly what to write when emailing an invoice, with seven templates you can copy, paste, and adapt — plus the subject lines, timing, and small details that get invoices opened and paid.
The anatomy of a good invoice email
Every invoice email needs five things, in this order:
- A clear subject line — invoice number + what it's for. Never a blank subject or just "Invoice".
- One line of context — what the invoice covers, in plain words.
- The key facts — amount, due date, and how to pay. Don't make the client open the PDF to find these.
- The invoice itself — attached as a PDF, never as an editable file or a link that requires login.
- A polite close — one line. Thank them, offer to answer questions, done.
Keep the whole email under 150 words. The invoice does the talking; the email just delivers it professionally.
Subject lines that get opened
The subject line is doing real work — many clients triage invoices by subject alone. Good patterns:
Invoice #INV-042 — Website redesign, due 21 OctInvoice INV-042 for September retainer (£1,500)Payment request: INV-042 — $2,400 due Oct 21
Always include the invoice number. If the client has a purchase order number, include that too — it helps their finance team match it instantly. Avoid vague subjects like "Invoice attached" or, worse, no subject at all.
Template 1: Sending a first invoice to a new client
This is the one people overthink. Keep it warm but businesslike — you're not apologising for asking to be paid.
Subject: Invoice #INV-001 — Logo design project, due 21 Oct 2026
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Hi Sarah,
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Thanks again for a great project — I've attached invoice #INV-001 for the logo design work (£850), due 21 October 2026.
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You can pay by bank transfer to the details on the invoice. Let me know if you need anything else from me, such as a different format or a PO reference added.
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Best,
Ammar
Note what it does: names the work, states the amount and due date in the body (not just the PDF), tells them how to pay, and anticipates the two most common admin frictions (format, PO number).
Template 2: Recurring monthly invoice
For retainers, routine beats creativity. Use the same format every month so the client's finance team recognises it instantly.
Subject: Invoice #INV-043 — October retainer (£1,500)
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Hi James,
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Attached is invoice #INV-043 for the October retainer (£1,500), due 7 November 2026. Same payment details as usual.
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Thanks,
Ammar
Consistency is the point. Same subject pattern, same layout, every month — it becomes part of their process instead of a surprise.
Template 3: Invoice with a deposit request
When you need money before starting, say so plainly and tie it to the next step.
Subject: Deposit invoice #INV-044 — 50% to begin project (£1,250)
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Hi Priya,
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As agreed, I've attached the deposit invoice (#INV-044) for £1,250 — 50% of the project total. Once this is received I'll get started and confirm the kickoff date.
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The balance (£1,250) will be invoiced on delivery. Payment details are on the invoice.
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Looking forward to it,
Ammar
Deposits work best when the trigger is explicit: this payment unlocks this next step. It turns the invoice from a demand into a doorway.
Template 4: Friendly payment reminder (a few days before the due date)
A pre-due-date nudge is not rude — it's good service. Many late payments are just forgotten payments.
Subject: Gentle reminder: Invoice #INV-042 due 21 Oct (£850)
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Hi Sarah,
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Just a heads-up that invoice #INV-042 (£850) is due on 21 October. I've re-attached it here in case it's buried in your inbox.
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Thanks!
Ammar
Send this 2–3 days before the due date. Re-attaching the invoice removes the client's easiest excuse ("I can't find it").
Template 5: Overdue invoice follow-up
The day after the due date, the invoice is overdue. Be direct, not emotional — and reference the agreed terms.
Subject: Overdue: Invoice #INV-042 (£850), due 21 Oct
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Hi Sarah,
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Invoice #INV-042 (£850) was due on 21 October under our Net 14 terms and appears to still be outstanding. Could you let me know when I can expect payment?
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I've attached a fresh copy. If there's an issue with the invoice itself, I'm happy to sort it out.
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Thanks,
Ammar
One line acknowledging possible problems ("if there's an issue") keeps the door open without conceding anything. Our chasing guide has the full escalation sequence if this doesn't resolve it.
Template 6: Final notice before escalation
When polite reminders haven't worked, say plainly what happens next. Specifics beat vague threats.
Subject: Final notice: Invoice #INV-042 (£850) — 30 days overdue
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Hi Sarah,
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Invoice #INV-042 (£850) is now 30 days overdue. Per our agreement, late payments accrue interest at 1.5% per month, which has been applied from 22 October.
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Please arrange payment by 28 November. If I haven't received it by then, I'll be passing this to formal collection.
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Ammar
Notice the tone shift: no "thanks!", no smiley warmth. You're still professional, but the friendliness dial is at zero — that's what signals seriousness. Check our guide to late fees on invoices to make sure your charges are enforceable before citing them.
Template 7: Thank-you after payment
Nobody does this, which is exactly why it works. A two-line thank-you after payment builds the relationship that gets your next invoice paid faster.
Subject: Thanks — payment received for INV-042
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Hi Sarah,
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Just confirming I've received payment for invoice #INV-042. Thanks for the quick turnaround — always a pleasure working with you.
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Ammar
Send it the same day the money lands. It costs you thirty seconds and makes you the supplier clients want to pay promptly.
Practical details that prevent problems
Always send a PDF. Not a Word doc, not a Google Docs link, not a photo of a spreadsheet. PDFs look professional, can't be accidentally edited, and print correctly. Our free invoice generator produces a clean PDF with one click — no signup, no watermark.
Name the file sensibly. INV-042_Acme-Corp_Oct-2026.pdf beats invoice_final_v2.pdf. The client saves it into their records; make that easy.
Send from a professional address. An invoice from [email protected] gets taken more seriously than one from [email protected]. And keep the same sending address every time so clients can filter reliably.
Put the amount and due date in the email body. Roughly half of recipients decide whether to act without opening the attachment. If the amount and date are in the body, the invoice can be approved from the inbox.
Time it right. Send invoices Tuesday to Thursday, mid-morning in the client's timezone. Monday inboxes are triage zones; Friday afternoons are where invoices go to be forgotten until next week.
Keep proof. Use read receipts sparingly (they're unreliable), but do keep your sent emails. If a payment dispute ever escalates, a clean paper trail of sent invoices and reminders is your best evidence.
Frequently asked questions
Should I send the invoice as an attachment or a link?
Attachment, always. A link that requires the client to log in, download an app, or view the invoice in your system adds friction — and some company firewalls block unfamiliar links outright. Attach the PDF directly.
What should I write in the email when sending an invoice?
Three things: what the invoice is for, the amount and due date, and how to pay. One short paragraph covers it. Attach the PDF, use a subject line with the invoice number, and close politely. Under 150 words total.
How soon after finishing work should I send the invoice?
Same day if possible, next morning at the latest. Every day you delay invoicing pushes your payment back by a day — and clients mentally file "work finished weeks ago" differently from "work finished yesterday". Fast invoicing signals professionalism.
Is it rude to remind a client before the invoice is due?
No — a brief reminder 2–3 days before the due date is standard business practice and most clients appreciate it. Late payments are usually forgetfulness, not malice. The reminder that feels awkward to send is the one that prevents the awkward overdue chase later.
What if the client says they never received my invoice?
This is why you re-attach the invoice with every reminder and keep your sent emails. Reply with a fresh copy the same day, confirm the email address they want invoices sent to, and ask them to confirm receipt. If it keeps happening, ask for an alternative contact in their finance team.