How to Send an Invoice to a Client

Creating the invoice is only half the job — how you send it affects how quickly it gets paid. Here's a practical approach to sending invoices and following up when they're overdue.

Send it as a PDF

PDF is the standard format for invoices because it looks the same on every device, can't be accidentally edited by the recipient, and is easy for accounting software to file. Avoid sending an invoice as an editable Word or spreadsheet file, and avoid pasting the details directly into an email body — a client's finance team generally expects an attached, self-contained document.

Write a short, direct email

The email that carries the invoice doesn't need to be long. State the invoice number, the amount, the due date, and attach the PDF. For example:

Subject: Invoice INV-0032 — due March 21 Hi Sam, please find invoice INV-0032 attached for the homepage redesign, total $1,200, due March 21. Let me know if you have any questions. Thanks!

This gives the recipient everything they need without making them open the attachment just to know what it's about.

Send to the right person

For individual clients, this is usually straightforward. For businesses, confirm whether invoices should go to your main contact, a dedicated billing address, or both. Sending it to the wrong inbox is one of the most common, avoidable reasons an invoice sits unpaid.

CC yourself, or keep a copy

Keep a record of every invoice you send — either by CC'ing yourself, saving a copy to a dedicated folder, or both. If a payment dispute comes up later, having the exact PDF and send date on hand saves a lot of back-and-forth.

Following up on overdue invoices

If a due date passes without payment, a short, polite follow-up is usually enough:

Hi Sam, just following up on invoice INV-0032, which was due March 21. Let me know if there's anything you need from me to get it processed. Thanks!

Keep the tone neutral and assume there's a simple explanation (an invoice missed in a busy inbox is common) rather than opening with an accusation. If a second follow-up is needed a week or two later, it's reasonable to be a bit more direct about the original due date and ask for a specific payment timeline.

A simple sending checklist

• Invoice exported as a PDF, not an editable file
• Sent to the correct contact or billing email
• Email states the amount and due date up front
• A copy kept for your own records
• A calendar reminder set for the due date, in case a follow-up is needed

Once you've built your invoice with our free generator, downloading it as a PDF takes one click — ready to attach and send straight away.