How to send an invoice by email

You've finished the work, exported the invoice, and now you're staring at an empty email window. The client may be ready to pay, but a vague subject line, a buried due date, or a broken attachment can turn a simple transaction into another week of chasing.

Treat the message as a payment step rather than a courtesy note. Put the invoice reference, the amount, the due date, and the payment action where the recipient can see them immediately, and use a tracked link when you need to know whether the invoice was opened.

Send it as a payment step, not a courtesy note

I spent ten years in growth roles sending documents to people I could not chase too hard, and "just sending it over" almost always meant the sender had finished their part, not that the recipient had a clear path to payment. The email reached the right person, then sat there while accounts payable tried to work out what the document was, how much it was for, and when it was due.

Email is still the practical bridge between paper invoices and structured electronic invoicing. A 2019 Billentis report on the European e-invoicing market found that among larger businesses, roughly two-thirds issue PDF invoices by email while fewer than 20% send structured e-invoices through EDI. That figure is dated now, and its scope is large companies rather than everybody, but the shape has not changed much: the PDF attached to an email is still the default. You can read the detail in the Billentis e-invoicing journey report.

Your opening email should answer four things without making the recipient search:

What is this: name the invoice and the work or order it covers.
How much is due: state the total clearly.
When is it due: put the date in the first paragraph.
What should happen next: give one payment action, ideally a direct link or clear bank payment instructions.

"Thanks again for the project. Invoice INV-1047 for the completed website work is attached. The total due is £2,400, payable by 30 June. You can pay securely using the link below" is far stronger than "Please find attached our invoice for your attention."

Get the invoice right before you open the email

Most delays start with missing information, not with poor writing.

What goes on the invoice

Your invoice should carry everything the client, the finance team, and the payment processor need to approve it without another message:

Invoice number: a unique reference that matches your accounting records.
Invoice date: the issue date, easy to find.
Due date: an actual calendar date, not "payable within agreed terms".
Customer details: legal business name, billing address, and the correct accounts payable contact.
Line items: the work, quantity, rate, tax, discount, and total.
Payment method: bank transfer, card, or whatever you agreed.
Bank details: for UK payments, the sort code and account number where relevant.
Payment link: if the recipient can pay online, give them the route.
Commercial terms: any early payment discount or late payment charge you actually intend to enforce.

If you are standardizing a template, what a UK invoice has to include is the reference worth working from, because it covers the legally required fields rather than the nice-to-have ones.

What to check before you send

Confirm the billing address, the accounts payable contact, the invoice number, and the total. Give the file a useful name, INV-1047-LiveDocument-June-2026.pdf rather than final_invoice_new.pdf.

If the client issued a purchase order, put that number on the invoice and in the email. Public sector teams often rely on automated matching, so the purchase order, billing department, invoice number, and attachment need to agree exactly.

The subject line and the first sentence do the work

The subject line should help the recipient identify the message. The body should help them pay.

Combine the invoice reference with the amount and the action:

Invoice INV-1047, £2,400 due 30 June
Payment requested, INV-1047 for June services
Invoice INV-1047, payment link inside

Avoid Invoice, A quick note, or Following up. They force the recipient to open the message before they know what it concerns. Keep it short enough to survive a phone screen, where anything past roughly forty characters gets cut.

Put the payment action above the fold

Your first sentence should contain the amount, the due date, and the payment route. Don't make the customer open a PDF to discover how to pay.

Use this template:

> Subject: Invoice INV-1047, £2,400 due 30 June > > Hi [Name], > > Thanks again for working with us. Invoice INV-1047 for [project or service] is due on 30 June, and the total is £2,400. > > Pay invoice securely: {{payment_link}} > > You'll also find the full invoice attached, including the work summary and bank details. If your accounts payable team needs a purchase order or a different billing format, tell me and I'll send it over. > > Thanks, > Cameron

The link should lead to the exact payment page, not your homepage or a generic account portal. Use one primary call to action. If the customer prefers a bank transfer, put those details in the email and repeat them on the invoice.

Politeness doesn't weaken a payment request. Vague language does. Replace "when you get a chance" with the agreed due date, and replace "please see attached" with the action you want.

Attachment or link

Attachments are familiar, but familiarity isn't the same as control. A PDF gives the recipient a fixed file they can save, forward, and upload into an accounting system. It also creates version risk, tells you nothing about engagement, and can be missed in a crowded inbox.

A shareable link gives you a live delivery layer. You send one URL, the recipient always lands on the current issued document, and viewing activity gives you a reason to follow up.

One limit that matters more for invoices than for anything else you send. An issued invoice is an accounting record, and quietly editing the amount, the tax, the due date or the terms behind a link that someone has already seen is not a version fix, it is a different invoice. If the figures change, issue a new invoice or a credit note and say so. Use the link to deliver the current document and to correct a typo, not to move the numbers after the fact.

The other trade-off is that some finance teams require a downloadable file or a structured invoice format, so a link isn't automatically suitable for every recipient.

Regulated workflows can remove the choice entirely. Germany's federal invoice portal, which is how you bill public sector bodies there, accepts email as a submission channel but takes exactly one structured e-invoice per message, in a format such as XRechnung, and rejects the message if extra attachments ride along. A tracked link is not a compliant submission there at all. That is a rule for billing German public bodies rather than a general one, but it is a good reminder to ask before you assume: read the German guidance on submitting e-invoices by email, and check what your own recipient's system requires.

Criteria	Attachment	Link
Recipient control	Fixed file that can be saved or uploaded	Browser-based access to the current document
Version management	Old copies can keep circulating	One destination shows the current issued document, though a changed figure still needs a reissue
Engagement visibility	Usually limited to delivery signals	Can support open and interaction tracking
AP compatibility	Familiar for many finance workflows	May need a downloadable invoice or approved portal
Email size	Adds a file to the message	Keeps the email lighter
Follow-up timing	You may not know if it was reviewed	Viewing activity can create a useful follow-up signal

My default is practical: attach the invoice when the client's AP process demands it, and use a tracked link when you need visibility or want to explain a complex bill. You can include both, as long as the recipient has one obvious payment route.

For a hosted document workflow, see share PDF as a link. Don't send multiple invoice files in one email when an automated system is expected to process them.

What a tracked link tells you, and what it doesn't

A delivery receipt tells you very little. A tracked document link can tell you the client opened the invoice, came back to it, and spent time on a particular page. That moves your follow-up from guesswork to timing.

I wouldn't call someone the moment they open an invoice. That can feel intrusive, especially if the person is reviewing it internally. I would use the signal to choose the right moment and the right context. If the client opens the document after you send it, you know the link resolved and the document loaded. If they reopen it after you ask whether anything is blocking payment, that's a reason to send a short, direct note.

Use the activity as a trigger, not a verdict

Create a link for the final invoice or supporting document.
Turn on alerts for opens and reopens.
Check which pages get attention, especially pricing, scope, terms, or payment instructions.
Follow up when the activity suggests active review, but don't assume an open means approval.
Record the interaction beside the invoice in your accounting or customer system.

An invoice is a financial document, and the activity you collect against it is personal data about the person reading it: who opened it, when, from roughly where, and for how long. Decide before you switch tracking on what you tell the recipient, who internally can see the viewer records, and how long you keep them. "We can see everything" is not a position you want to be explaining to a client's finance team after the fact.

Page-level activity is most useful when an invoice carries more than a total. A professional services bill may include a work summary, expense detail, or a change order explanation. If the recipient keeps returning to one section, address that section directly instead of sending another generic reminder.

PDF tracking software is worth it when the document itself carries context your team needs a record of. It is not accounting software, though, and it will not raise the invoice or take the payment. It carries the document and tells you it was read.

Tracking won't fix an incorrect invoice or replace a finance approval. It gives you timing.

Set the reminder before you need it

Send the invoice immediately after the agreed work or billing milestone. The delay starts when you postpone the first message.

A reminder-first workflow beats a single send. Trove, which automates invoice chasing for small businesses, published figures from its own customer data: of the invoices it chased that were eventually paid, 58% were paid after one reminder and another 21% after a second. Note the denominator. Invoices that never got paid at all were excluded from that sample, so read Trove's reminder figures as evidence that reminders work rather than as a recovery rate you can forecast against.

An escalation ladder that stays polite

Initial email: the invoice with the amount, due date, and payment link.
First reminder: shortly after the due date. Neutral tone, ask whether the client needs anything to process it.
Second reminder: state that the invoice is overdue, repeat the amount and payment route, ask for a payment date.
Escalation: contact the accounts payable owner or the commercial contact, and keep a written record.

A first reminder can say:

> Hi [Name], I'm checking on invoice INV-1047 for £2,400, which was due on 30 June. Could you confirm whether it's in your payment queue? You can use this payment link: {{payment_link}}.

The second should be firmer:

> Hi [Name], invoice INV-1047 remains unpaid. Please confirm the expected payment date today, or let me know if there's an issue with the invoice or the payment details.

Keep every reminder tied to the same invoice reference. If you want the broader operating context, how to increase sales covers commercial follow-up generally, but overdue billing deserves its own short sequence.

Where to start

A good invoice email does three jobs: it identifies the charge, removes payment friction, and creates a clear follow-up path. The attachment versus link decision matters, but the bigger question is whether the recipient can understand and act on the request without opening another thread.

Standardize your invoice fields and your subject line. Put the amount, due date, and payment route in the first sentence. Choose attachments for strict AP workflows and tracked links when visibility improves your timing. Set the first reminder before you send the invoice, so chasing payment becomes a process rather than a personal negotiation.

I've watched enough proposals, decks, and invoices disappear into inboxes to know that silence isn't always rejection. Sometimes the recipient never saw the file. Sometimes they opened it and didn't know what to do next.

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LiveDocument lets you share a PDF as one tracked link, add a short video walkthrough, and get real-time alerts when someone opens or revisits it. Visit LiveDocument to turn invoice delivery into a clearer, more trackable payment workflow.