A well-written invoice email is more than just a payment request. Done right, it can encourage prompt payment, reduce the risk of unpaid invoices, and help maintain a steady, healthy cash flow for your business.
Payment delays can cause serious financial strain, making it harder to manage daily operations. According to the 2025 Intuit QuickBooks Small Business Late Payments Report, 56% of small businesses surveyed are owed money from unpaid invoices, averaging $17,500 per business.
Sending a clear and professional invoice email is one of the most effective ways to ensure you receive payment on time. Here’s how to write an invoice email, a step by step for what to include, and a customizable template.
What to include in an invoice email
The objective of an invoice email is to make it easy for your client to pay you. The easier you make it, the sooner you get your money. This means including all of the necessary details in a clear, concise format:
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A descriptive subject line. Make it immediately clear what the email is about by including the word “Invoice,” your unique invoice number, and your business name.
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A professional and polite message. This sets a positive context for your payment request and can help to strengthen your client relationship.
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Business branding and contact information. Include your logo and contact information in the email signature.
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The attached invoice. Always attach the actual invoice as a PDF document to ensure the formatting remains consistent and prevents the document from being easily altered.
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Payment details and instructions. Clearly state your accepted payment methods, whether that’s a bank transfer, a secure online payment link, or something else.
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Payment terms. Clearly state the payment due date and your policy on late fees or overdue payments.
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Invoice details. Put a quick summary of the most important details directly in the email body, including the invoice number, invoice date, and total outstanding balance.
How to write an invoice email
- Craft a clear and concise email subject line
- Use a professional and polite salutation
- Start with a positive opening
- Clearly state the purpose of the email
- Provide a summary of the invoice details
- Include clear payment instructions
- Attach the invoice
- Conclude with a polite closing and signature
Follow these steps to create an effective invoice email that helps reduce payment delays and encourages timely payments:
1. Craft a clear and concise email subject line
A clear subject line is your first opportunity to convey the purpose of your email. This simple step helps ensure your message isn’t overlooked in a busy inbox.
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Action. Create a subject line that grabs attention and clearly states the email’s purpose.
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Best practice. Use a format like “Invoice [Invoice number] from [Your business name] for [Project/service].” This makes it easier for the client to find the invoice when they’re ready to pay, or when they’re reviewing their finances.
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What to avoid. Don’t use vague subject lines like “Payment” or “Important message.” These can be easily missed, ignored, or even sent to a spam folder. Keep your subject line concise so it doesn’t get cut off if viewed on a mobile device.
2. Use a professional and polite salutation
Starting with a personalized greeting sets a respectful and professional tone for the entire message. It shows the client you value your relationship.
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Action. Address the recipient by their name.
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Best practice. Start with “Hi [Client name],” or “Dear [Client name],” or a personalized greeting, which is generally better than a generic one.
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What to avoid. Don’t use greetings like “To whom it may concern” or “Hello.” These are impersonal and can make you seem less professional.
3. Start with a positive opening
A quick thank you at the beginning of your email serves two purposes: It sets a positive tone and reinforces the goodwill between you and your client.
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Action. Begin the message with a brief, polite thank you.
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Best practice. Say something like “Thank you again for the opportunity to work with you on [Project name].” This starts the email on a positive note and sets a professional tone for the payment request.
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What to avoid. Don’t jump straight into demanding payment. This can come across as aggressive and potentially damage the relationship.
4. Clearly state the purpose of the email
Get straight to the point. Inform the client that an invoice is attached to remove any guesswork and speed up the process.
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Action. Let the client know the email includes the invoice for your services.
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Best practice. Use a clear line like, “Please find the attached invoice for the services provided.”
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What to avoid. Don’t be vague—being direct saves time and avoids confusion.
5. Provide a summary of the invoice details
Although the full invoice is attached, a quick summary in the email body provides a convenient snapshot of the amount and due date, saving the client from having to open a separate document.
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Action. Include a quick summary of the key invoice details directly in the body of the email.
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Best practice. List the invoice number, invoice date, amount due, and due date.
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What to avoid. Don’t force them to open the attached invoice to find out how much they owe or when it’s due.
6. Include clear payment instructions
Making it easy for your client to pay is one of the most effective ways to ensure timely payment. By providing clear, actionable instructions, you eliminate any potential friction in the payment process.
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Action. Specify your accepted payment methods and provide a direct link or account details.
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Best practice. If you have an online payment portal where customers can make payments directly, provide a link and include language like “You can make a secure online payment by clicking the following link: [Payment link].” If you prefer a bank transfer, provide your bank account details. Give clear instructions to ensure timely payments.
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What to avoid. Don’t make the client hunt down this information on your website or in the attached invoice.
7. Attach the invoice
The invoice itself is the most important piece of the process. Attaching it in a professional, secure format is essential.
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Action. Attach a high-quality PDF of the invoice: a clear, professional-looking, and error-free digital invoice that’s easy to read and properly formatted for printing or digital sharing.
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Best practice. Use a file name that is easy to identify, such as “Invoice [Client name] [Invoice number].pdf.” This makes it easy for the client to save and file the document.
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What to avoid. Don’t send the invoice as an image file or in a format that can be easily edited or corrupted.
8. Conclude with a polite closing and signature
To leave a positive impression, end your email with a professional closing and a full signature.
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Action. End the email with a polite closing, your full name, and contact information.
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Best practice. Use a professional closing, like “Sincerely” or “Best regards,” followed by your name, title, business name, and other contact details. This reinforces your credibility and professionalism. Be sure to proofread the invoice email to ensure there aren’t any errors.
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What to avoid. A curt or abrupt sign-off can come across as unprofessional.
How to write an invoice email FAQ
What do you write in an email when sending an invoice?
When sending an invoice, write a polite and professional message that states the purpose of the email. It should include the invoice number, the amount due, the due date, and clear payment instructions. Be sure to always attach the invoice as a PDF.
How do I write a simple invoice?
A simple invoice is a formal document that includes your business’s name, logo, and contact details, as well as the client’s name and contact details. A unique invoice number, the invoice date, and a detailed list of the services provided (including descriptions, quantities, and costs) are also necessary. Don’t forget to include the total outstanding balance and payment terms, including the due date and accepted payment methods. You can use invoicing software or a pre-made invoice template to ensure you include all the necessary details.
What does an invoice email look like?
An invoice email is clean and easy to read and has a clear subject line and a professional body message summarizing the key details of the attached invoice and all the information the client needs to make a prompt payment. It’s essentially a payment request and an integral part of the invoicing process.
