How to Send an Invoice by Email

Prepare the invoice before sending it

Before opening your email, review the invoice carefully. Correcting mistakes before the invoice reaches the customer can prevent delays and reduce the need to issue a replacement.

Check that the invoice includes the correct customer details, invoice number, issue date, payment due date, descriptions, prices, taxes, payment instructions, and final amount due.

Choose the correct invoice format

PDF is usually the most suitable format for an invoice sent by email. It preserves the layout of the document and can be opened on most computers, phones, and tablets.

Avoid sending an editable file unless the customer has specifically requested one. A PDF looks more professional and reduces the chance of information being changed accidentally.

Use a clear filename

Give the invoice file a name that helps both you and the customer identify it easily. A filename such as Invoice-1048-Bright-Solutions.pdf is more useful than a generic name such as document.pdf.

Including the invoice number, business name, customer name, or project reference can make the file easier to store and find later.

Send the invoice to the right person

Make sure the invoice is being sent to the person or department responsible for payment. For smaller customers, this may be your usual contact. Larger businesses may require invoices to be sent directly to an accounts payable or finance email address.

Sending the invoice to the wrong recipient can add several days to the payment process while it is forwarded internally.

Write a clear subject line

The email subject line should make the purpose of the message obvious. Include the word invoice and, where useful, the invoice number, customer name, or project name.

For example, Invoice 1048 from Bright Solutions is clear and easy for the customer to recognise. Avoid vague subject lines such as Document Attached or Payment.

Keep the email message short

An invoice email does not need to contain a long explanation. A brief greeting, a sentence explaining that the invoice is attached, and a polite closing are normally enough.

You can also mention the invoice number, amount due, payment deadline, and preferred payment method when this information would be helpful.

Example of an invoice email

A simple invoice email could say: Hello Sam, please find attached invoice 1048 for the website maintenance completed in July. The total amount due is £450 and payment is due by 31 July 2026. Please let me know if you have any questions. Kind regards, Alex.

This gives the customer the key information without making the message unnecessarily long.

Attach the invoice before sending

Forgetting the attachment is one of the easiest mistakes to make when sending an invoice. Attach the PDF before writing the email or check the attachment area carefully before pressing send.

Open the attachment once to confirm that it is the correct invoice and that the document displays properly.

Include payment instructions

The invoice itself should contain the main payment instructions, but you may also include a short reminder in the email.

For example, you could explain that payment can be made by bank transfer and ask the customer to use the invoice number as the payment reference.

Should you request confirmation?

For important or high value invoices, it may be helpful to ask the customer to confirm receipt. This gives you confidence that the invoice reached the correct person.

For routine invoices, a confirmation request may not be necessary. You can instead follow up if the customer does not acknowledge the invoice or make payment by the agreed date.

Keep a record of the email

Keep the sent email and a copy of the invoice for your records. This allows you to confirm when the invoice was issued, who received it, and which document was attached.

Organised records are useful if the customer later says that the invoice was not received.

Follow up when necessary

If you do not receive confirmation and the invoice is important, send a short follow up after a reasonable period. If the due date passes without payment, send a polite payment reminder.

Keep the original invoice attached or include the invoice number so the customer can locate it quickly.

Common mistakes when emailing invoices

A final check can prevent many common problems.

Mistakes to avoid include:

• Sending the invoice to the wrong email address
• Forgetting to attach the invoice
• Attaching the wrong invoice
• Using an unclear subject line
• Leaving out the payment due date
• Providing incorrect payment details
• Sending an invoice with calculation errors

Send every invoice professionally

A professional invoice email should be clear, accurate, and easy for the customer to process. Use a recognisable subject line, attach the correct PDF, include a short message, and make payment instructions easy to find.

Following the same process for every invoice can reduce mistakes and help customers approve and pay your invoices more quickly.