Last Updated October 8, 2025
Invoicing customers by email is second nature for experienced business owners, but new entrepreneurs may not realize the value in learning how to effectively create and send an invoice. The right formatting and phrasing can have a huge impact on how often you get paid on time, not to mention its impact on customer relationships.
A clear, professional message paired with a well-structured invoice email template can help you settle invoices faster, reduce back-and-forth, and stabilize cash flow. In this guide, you’ll learn why invoice emails matter and a five-step process for writing invoice emails that get results.
Key Takeaways
- Sending invoices by email is faster and more efficient, and a clear, professional message improves payment speed.
- Accurate invoices with all key details help build client trust and reduce delays or confusion.
- Using templates for regular or overdue invoices saves time while keeping communication consistent and polite.
- Following up strategically with reminders, calls, or escalation ensures overdue payments are addressed without damaging relationships.
Why Learning How to Write an Invoice Email Is Important
Slow-paying customers lead to business cash flow problems. While proper collection practices definitely play a role here, how you approach the invoice itself also matters.
Mastering how to write an invoice email helps you build strong relationships with clients, and it also means you tend to get paid faster. After all, when clients know exactly what the invoice is for, when it’s due, and how to pay, they’re far less likely to delay paying it. A clear, professional message paired with a well-structured invoice email template can accelerate payment, which in turn improves cash flow.
How to Send an Invoice Over Email
Whether you’re sending an invoice email to a new customer or a long-standing client, the right approach makes all the difference. Follow these five steps to confidently send an invoice via email.
1. Create Your Invoice
First, prepare the invoice itself. The format will differ depending on the type of invoice you need to send.
Go with a B2B invoice template if you work with enterprise clients, or opt for a small business invoice template that helps your startup look professional.
Whether you’re using accounting software, a template, or creating one manually, always double-check invoice details like:
- Amount owed
- Due date
- Payment instructions
Inaccuracies hurt client trust and can lead to accounting issues. Accuracy is a must for getting paid fast, and it sets the foundation for a smooth process when you send an invoice via email.
2. Add a Subject Line
The email subject line should leave no doubt about the email’s purpose. For example, use a clear subject line like, “Invoice #1024 – Due August 15.” These types of subject lines may not be clever, but they eliminate confusion and ensure clients don’t overlook your email in a crowded inbox.
3. Draft Your Message
Unless you work with only a single client, you’re likely sending multiple invoices at once. Writing messages from scratch is a great way to foster client relationships, but that takes a significant amount of time.
Instead, use a template for the invoice email itself. Using a pre-built email template for sending invoices saves time and keeps your communications consistent. If this feels too impersonal, consider creating a template for each client, so they receive a personalized message tailored to their needs.
You may need different templates for various situations. For example, asking a client to address a late invoice can be tricky, so go with an email template you can use to politely ask for past-due payment without losing the account.
4. Attach the Invoice
Next, attach the invoice to the email. Always include the invoice as a PDF or other universally accessible format. If you’re wondering how to send an invoice email with the document attached, the key is to clearly mention in the body that the document is attached for the client’s reference.
5. Send the Message and Track Delivery
It helps to proofread the message one last time before sending it. Typos or missing information can delay payment. Carefully review the email before you send the invoice to ensure it’s polished and professional. Editing tools like the Grammarly browser extension can identify and fix spelling issues. Take this time to also ensure the invoice PDF is attached to the email.
If the message looks good, send an invoice to the customer’s billing contact. If possible, send this as a tracked message. Many invoicing platforms allow you to see when a client has viewed your message, giving you peace of mind that the customer received the invoice.
Invoice Email Template
How do you phrase an invoice email? Many businesses use the same template for run-of-the-mill invoices. While you’ll need a different template for situations like late payment or refunds, this invoice email template is a great starting point:
Subject line: Invoice #12345 from [Your company name] – Due [Due date]
Dear [Client name],
I hope you’re doing well! Thank you again for letting us [complete the project / provide services] for [Client company name]. Attached is Invoice #12345, which is for [brief description of goods/services], and it’s due on [Due date].
If you have any questions about the details or need any changes, please let me know—I’m happy to help.
Payment details:
- Amount Due: $X,XXX.XX
- Payment Methods: [Bank Transfer / Credit Card / PayPal / etc.]
- Invoice Attached: Yes
Thank you for your business! I appreciate your prompt attention to this invoice.
Best regards,
[Your Name]
[Your Position]
[Company Name]
[Contact Information]
How to Write an Email for an Overdue Invoice
Most late invoices happen accidentally, especially when you send an invoice via email, where it can get lost in the client’s inbox. Knowing how to write an email to collect an unpaid invoice is a critical skill. Even the most reliable clients can miss a payment deadline, and a well-written message often makes the difference between receiving payment quickly and chasing invoices for weeks.
When crafting this type of message, keep it polite but firm. A friendly invoice reminder email should:
- Reference the original invoice. Include the invoice number, date, and amount. Better yet, reattach the original invoice for clarity.
- Assume positive intent. Don’t use accusatory or frustrated language. Frame this as a gentle nudge instead of as an accusation.
- Reiterate payment instructions. Make it as easy as possible for the client to pay you.
- Set expectations. This is where you hold firm. Outline the next steps of what will happen if you don’t receive payment by a specific date.
What to Do if a Client Doesn’t Pay
Sometimes, even after multiple reminders, a client still won’t respond or settle their balance. Unfortunately, this means you need to escalate by:
- Sending follow-up messages: After your first friendly invoice email, schedule a second and third reminder, each progressively firmer in tone. You may need to CC additional people on the email, such as the CEO or another billing contact.
- Calling them: Email is convenient, but many clients have crowded inboxes that hide important invoice reminders. If a client isn’t responding via email, call them to chat about the invoicing issue.
- Pausing work: Inform the client that you must pause all work until they address the outstanding invoice.
- Considering outside help: If you’ve tried everything and the client won’t pay, you may need to send them to collections or hire a lawyer.
In-Summary: How to Write an Invoice Email
Learning how to write an invoice email is one of the simplest ways to improve your cash flow and reduce payment anxiety. Using a polished invoice email template and carefully crafted wording will go a long way to ensuring clients respond quickly.
Setting expectations through strong communication helps, but not all clients will pay on time. When payments slip through the cracks, understanding how to write an email for an overdue invoice helps you maintain client relationships while getting paid on time. The key is to be clear, professional, and consistent in everything you do.
Michael McCareins is the Content Marketing Associate at altLINE, where he is dedicated to creating and managing optimal content for readers. Following a brief career in media relations, Michael has discovered a passion for content marketing through developing unique, informative content to help audiences better understand ideas and topics such as invoice factoring and A/R financing.
