How to Send a Professional Invoice: Best Practices + Email Templates
The way you send an invoice is almost as important as the invoice itself. A sloppy send = delayed payment. Here’s how to get it right.
Step 1: Make sure your invoice is correct before sending
Sending an incorrect invoice delays payment and damages trust. A quick pre-send check takes 60 seconds and saves days.
✅ Pre-send checklist
- ✓ Correct client email address
- ✓ Correct amount (and currency)
- ✓ Correct due date
- ✓ Sequential invoice number (no gaps or duplicates)
- ✓ PDF format — not Word, not an image, not a Google Doc link
- ✓ VAT: correct rate applied and VAT number shown if required
Step 2: Write a professional invoice email
Use this subject line formula every time: Invoice #[N] for [project/service] — due [date]
It’s clear, searchable, and immediately tells the recipient what action they need to take.
Template 1 — Standard invoice
Subject: Invoice #0042 for website redesign — due 14 June 2026
Hi [Name],
Please find attached Invoice #0042 for £2,500 for the website redesign project completed on 15 May 2026.
Payment is due by 14 June 2026 (Net 30).
You can pay by:
• Bank transfer: [IBAN/sort code and account]
• Online: [payment link]
Please let me know if you have any questions.
Best regards,
[Your name]
Template 2 — Milestone invoice
Subject: Invoice #0043 — Project milestone 2 of 3 — due [date]
Hi [Name],
Milestone 2 of 3 is complete. Please find attached Invoice #0043 for [amount] covering [deliverable].
Payment is due by [date]. The final milestone invoice will follow upon project completion.
Best regards,
[Your name]
Template 3 — Recurring invoice
Subject: Monthly invoice — May 2026 — due [date]
Hi [Name],
Please find attached your monthly retainer invoice for May 2026 — Invoice #0044 for [amount].
Payment is due by [date]. Thank you for the continued partnership.
Best regards,
[Your name]
Stop chasing. Start automating.
Chaser sends escalating invoice reminders automatically. Add an invoice once — Chaser handles the rest. Free for 3 invoices.
Try Chaser free →No credit card required
Step 3: Timing matters
- ✅Best time to send: Monday–Wednesday, 9–11am (client’s local time)
- ❌Avoid: Friday afternoon — forgotten over the weekend, invoice ages before anyone sees it
- →Project milestones: send the invoice the same day you deliver the work
- →Retainers: send on the 1st of the month, due on the 15th or end of month
- →Hours tracked: send within 24 hours of the billing period ending
Step 4: Follow up automatically
Manual follow-up is emotional. You second-guess yourself, feel awkward, and often wait too long. Automated follow-up is consistent, professional, and works while you sleep.
Day 7 after due date
Friendly reminder — assume they forgot
Day 14 after due date
Firmer follow-up — express urgency
Day 21 after due date
Formal notice — mention next steps
Day 30 after due date
Final escalation — collections warning
Chaser automates all 4 stages from day one. You set it up once and never have to think about it again.
Common invoice sending mistakes
Wrong email address
Always verify the billing contact before sending — not just the project contact.
Forgot to attach the PDF
Send it twice if needed — a follow-up "oops, forgot the attachment" email is better than no invoice.
Sent too late after completing work
Same day = best. Every day you wait to send is a day added to your payment timeline.
No payment link or clear payment instructions
Don't make clients dig for how to pay. Put IBAN, payment link, or Stripe link right in the email body.
"Let me know when you've paid"
Track it yourself. Don't rely on the client to update you — that's what invoice software is for.
Sending from a personal Gmail
Use a professional email address (you@yourdomain.com). Gmail suggests the invoice came from a side project, not a business.
Stop chasing. Start automating.
Chaser sends escalating invoice reminders automatically. Add an invoice once — Chaser handles the rest. Free for 3 invoices.
Try Chaser free →No credit card required
Frequently asked questions
What’s the best format to send an invoice?
PDF is the universal standard — it looks professional, can’t be accidentally edited, and is accepted by all accounting software. Avoid Word documents, Google Docs links, or image files.
What should I write in the email when sending an invoice?
Keep it brief and professional. State the invoice number, what it’s for, the amount, and the due date. Include payment instructions directly in the email body — not just in the PDF attachment.
When is the best time to send an invoice?
Monday to Wednesday, 9–11am is optimal. Avoid Friday afternoons — invoices sent then tend to be forgotten over the weekend. Send milestone invoices the same day work is completed.
What if I sent the invoice to the wrong email?
Resend with a corrected note: “Hi, I’m resending this invoice as the previous one may have gone to the wrong email. Please disregard the previous send.” Then follow up with a quick call to confirm receipt.
Should I call a client when sending a large invoice?
For large invoices (e.g., over €5,000), a brief heads-up call is good practice: “I’ll be sending invoice [N] for [amount] today — please let me know who to address it to.” This speeds up internal approval.