How to Send an Invoice by Email: Templates & Best Practices

Knowing how to send an invoice by email professionally can mean the difference between getting paid in days versus chasing payments for months. The email that accompanies your invoice matters almost as much as the invoice itself — it sets expectations, provides context, and makes it easy for the recipient to take action. Research from Xero shows that invoices sent with a clear, concise email and a direct payment link get paid an average of 15 days faster than those sent as bare attachments.

Anatomy of a Professional Invoice Email

What should an invoice email include? A clear subject line with the invoice number and amount, a brief description of what the invoice covers, the payment due date, accepted payment methods, and the invoice attached as a PDF or linked for online viewing.

Every invoice email needs five components:

1. Subject line — scannable and informative
2. Greeting — professional and personalized
3. Body — brief context on what the invoice covers
4. Payment details — due date, amount, how to pay
5. Attachment or link — the actual invoice

Keep it short. The email is not the invoice — it's the cover letter. Three to five sentences in the body is ideal.

Invoice Email Templates

Template 1: Standard Invoice Email

Subject: Invoice #[NUMBER] from [Your Business] — $[AMOUNT] due [DATE]

Hi [Client Name],

Please find attached invoice #[NUMBER] for [brief description of work, e.g., "website development services completed in January 2026"].

Amount due: $[AMOUNT] Due date: [DATE] Payment methods: [Bank transfer / credit card / PayPal — include link]

If you have any questions about this invoice, please don't hesitate to reach out.

Thank you for your business.

Best regards, [Your Name] [Your Business]

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Template 2: First Invoice to a New Client

Subject: Invoice #[NUMBER] from [Your Business] — $[AMOUNT]

Hi [Client Name],

Thank you for choosing [Your Business]. It's been a pleasure working with you on [project name].

Attached is my first invoice for [description of completed work]. Here are the details:

Invoice number: [NUMBER] Amount due: $[AMOUNT] Due date: [DATE] ([payment terms, e.g., Net 30]) How to pay: [Include payment link or bank details]

I've set up [payment terms] as we discussed. If you need me to adjust anything — billing contact, PO number, or payment method — just let me know.

Looking forward to continuing our work together.

Best regards, [Your Name]

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Template 3: Recurring Invoice Email

Subject: Monthly invoice #[NUMBER] — [Month Year] — $[AMOUNT]

Hi [Client Name],

Here's your monthly invoice for [service description] covering [month/period].

Invoice: #[NUMBER] Period: [Start date] — [End date] Amount: $[AMOUNT] Due: [DATE]

Pay online here: [payment link]

As always, reach out if you have any questions.

Thanks, [Your Name]

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Template 4: Gentle First Reminder (1-3 Days Overdue)

Subject: Friendly reminder: Invoice #[NUMBER] — $[AMOUNT] was due [DATE]

Hi [Client Name],

I hope this message finds you well. I wanted to follow up on invoice #[NUMBER] for $[AMOUNT], which was due on [date]. It's possible this slipped through — I know how busy things get.

For your convenience, I've reattached the invoice. You can pay via [payment method/link].

Please let me know if you have any questions or if there's anything holding up payment on your end.

Best regards, [Your Name]

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Template 5: Firm Second Reminder (7-14 Days Overdue)

Subject: Overdue: Invoice #[NUMBER] — $[AMOUNT] — Action required

Hi [Client Name],

I'm following up regarding invoice #[NUMBER] for $[AMOUNT], originally due on [date]. This invoice is now [X days] overdue.

Could you please confirm when I can expect payment? If there's an issue with the invoice or a question about the work delivered, I'm happy to discuss.

As noted in our agreement, a late fee of [X%] may apply to overdue balances. I'd like to avoid that, so please let me know how we can resolve this.

The invoice is reattached for your reference. Pay online: [link]

Thank you, [Your Name]

For more strategies on recovering overdue payments, see our guide to handling unpaid invoices.

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Template 6: Final Notice (30+ Days Overdue)

Subject: Final notice: Invoice #[NUMBER] — $[AMOUNT] — [X days] overdue

Hi [Client Name],

This is a final notice regarding invoice #[NUMBER] for $[AMOUNT], issued on [original date] with a due date of [due date]. Payment is now [X days] overdue.

I've attempted to reach you on [previous contact dates]. Per our agreement, a late fee of $[amount] has been applied, bringing the total to $[new total].

Please remit payment by [final deadline — typically 7 days from this email]. If payment is not received by this date, I will need to [escalate to collections / engage a mediator / pursue legal remedies].

I would prefer to resolve this directly. If there are circumstances affecting payment, please contact me so we can discuss a resolution.

Invoice attached. Pay online: [link]

Regards, [Your Name]

Best Practices for Invoice Emails

Write Subject Lines That Get Opened

Your subject line determines whether your email gets opened or buried. Include three things:

1. The word "Invoice" — so it's immediately identifiable
2. The invoice number — for easy reference
3. The amount and/or due date — creates urgency

Good examples:

• "Invoice #247 from Acme Design — $2,400 due Feb 28"
• "January services invoice — #INV-2026-012 — $850"

Bad examples:

• "Invoice" (too vague)
• "Please pay" (no context, feels aggressive)
• "Attached document" (spam filter territory)

Attach the Invoice as a PDF

Always attach the invoice as a PDF — it's universally readable, can't be accidentally edited, and maintains your formatting. Name the file clearly: Invoice-247-AcmeDesign-Feb2026.pdf is better than invoice.pdf or doc1.pdf.

Even better, include both a PDF attachment and an online payment link. InvoiceQuickly generates both automatically — clients can view the invoice online and pay directly, or download the PDF for their records.

Send During Business Hours

According to research from HubSpot, emails sent Tuesday through Thursday between 9-11 AM in the recipient's time zone have the highest open rates. Apply this to invoice emails. An invoice sent at 2 AM on a Saturday gets buried under Monday morning's inbox avalanche.

Copy the Right People

For B2B invoices, send to both your direct contact and the accounts payable department (or finance team). Ask your client: "Who should receive invoices?" during onboarding. This one question prevents weeks of "I forwarded it to accounting" delays.

Include a Direct Payment Link

Every extra step between "I should pay this" and "payment submitted" reduces the likelihood of prompt payment. A clickable "Pay Now" link in your email body removes friction. Services like Stripe and PayPal offer hosted payment pages that work well for this.

When to Send Your Invoice Email

Timing impacts payment speed more than most freelancers realize. The short version:

• Milestone work: Send the invoice the same day the deliverable is submitted
• Completed projects: Invoice within 24 hours of delivery
• Recurring services: Send on the same date each month, ideally the 1st or 15th

For a deeper dive into timing strategies backed by data, read our guide on when to send an invoice.

Automating Invoice Emails

If you're sending more than a handful of invoices per month, manual emailing becomes a bottleneck. Modern invoicing tools handle the entire send-and-follow-up cycle for you:

• Automatic sending: Schedule invoices to send on specific dates
• Payment reminders: Automatic follow-ups at intervals you choose (3 days, 7 days, 14 days overdue)
• Read receipts: Know when a client opens your invoice
• Online payment: Clients click a link and pay instantly

InvoiceQuickly's Autopilot handles all of this — from initial send to payment reminders — so you can focus on client work instead of inbox management.

Checklist Before Hitting Send

Before sending any invoice email, run through this list:

• Invoice number is unique and sequential
• Client name and billing details are correct
• All line items match the agreed scope
• Tax calculations are accurate
• Due date is clearly stated
• Payment instructions are included
• PDF is attached and opens correctly
• Subject line includes invoice number and amount
• Email is addressed to the right person (and CC'd to AP if applicable)
• Payment link is working

Need to make sure your invoice itself has everything it needs? Cross-reference our complete invoice checklist.

Create and send professional invoices in seconds with InvoiceQuickly →