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TemplatesLast updated July 24, 2026

The invoice email: what to write

An invoice email needs three things: a subject line with the invoice number, amount, and due date; one or two sentences of body referencing the work; and the invoice attached as a PDF with a payment link. Everything else slows the payment down — the email is the envelope, the PDF is the document.

The first send

Subject: Invoice #0014 — $2,400, due Aug 23. Body:

Template — first send
Hi Dana,

Thanks again for the website project. Invoice #0014 for $2,400 is
attached, due Aug 23 (net-30). You can pay online here: [payment link]

Let me know if anything on it needs adjusting.

Best,
Aaron

The +7 reminder

Past due by a week — friendly, assumes good faith, re-attaches everything so nobody digs:

Template — 7 days past due
Subject: Re: Invoice #0014 — $2,400, now past due

Hi Dana — a quick nudge on invoice #0014 ($2,400), which came due
Aug 23. The PDF and payment link are below. If it's already in
process, ignore me!

The +14 follow-up

Two weeks past due — direct, references the agreement, proposes a concrete resolution:

Template — 14 days past due
Subject: Invoice #0014 — 2 weeks past due

Hi Dana — invoice #0014 ($2,400) is now two weeks past the Aug 23
due date we agreed. Can you confirm payment will go out this week?
If there's an issue with the invoice itself, tell me today and
I'll fix it. Otherwise I'll call Thursday to sort it out.

What delays payment

Vague subjects ('Invoice attached'), editable attachments (send PDF, never .docx — see why the export step matters), missing payment links (every extra step the client takes is days added), and burying the amount. The reminders are also exactly the kind of thing worth automating — the system nags on schedule so you don't have to draft these at all.

More guides: What does net 30 mean? · Invoice vs. receipt: what's the difference? · A complete freelance invoice, annotated

Frequently asked questions

What should the subject line of an invoice email be?
Invoice number, amount, due date: 'Invoice #0014 — $2,400, due Aug 23'. The AP person searching their inbox in three weeks finds it instantly, and the amount being visible pre-open speeds approval.
Should the invoice be in the email body or attached?
Attached as a PDF, with a one-line summary and payment link in the body. The PDF is the document of record; body-only invoices get mangled by email clients and can't be filed.
How do I politely remind a client to pay an invoice?
At +7 days: one friendly line re-attaching the invoice and link, with an 'ignore if already paid'. At +14: direct, referencing the agreed terms, asking for a payment date and offering to fix any issue with the invoice. Keep every message assuming good faith until a call is warranted.
When should I send the invoice email?
The day the work is delivered or the milestone hits — and business-morning sends get processed faster than Friday-evening ones. Every day between delivery and invoicing extends the client's payment clock for free.