How to Send an Invoice (And Get Paid Faster)

Making an invoice is only half the job - how you send it has a big effect on how quickly you get paid. This guide covers the main ways to send an invoice, exactly what to write in the email, what to attach, and how to follow up if payment is late.

Ways to send an invoice

There are three common ways to deliver an invoice, from slowest to fastest to get paid:

Email a PDF. The traditional method: attach a PDF invoice to an email. It works everywhere, but the client still has to arrange payment separately, which adds friction and delay.
Send with an online payment link. The fastest option. The client opens the invoice and pays by card or bank transfer in a couple of clicks. Invoices with a built-in pay link get paid noticeably faster than PDFs.
Share through a client portal. For ongoing relationships, a portal lets clients view all their invoices, pay, and download receipts in one place.

Whichever you choose, always send a PDF copy or a permanent link - never just paste numbers into an email body, which looks unprofessional and is easy to lose.

How to write an invoice email

Keep the email short, friendly, and clear. It should tell the client what the invoice is for, how much, when it is due, and how to pay. Here is a template you can copy and adapt:

Subject: Invoice #0001 from [Your Business] - due [date]

Hi [Client name],

Thanks again for your business. Please find invoice #0001 attached for [brief description of work], totaling [amount].

The invoice is due by [due date]. You can pay securely online using the link below - it takes about a minute.

[Pay invoice button or link]

Any questions, just reply to this email. Thanks so much!

[Your name]

That is all it takes. A clear subject line with the invoice number and due date, a one-line summary, the amount, and an obvious way to pay.

What to include when you send an invoice

A unique invoice number in both the email subject and the invoice itself
The total due and the due date, stated plainly
Clear payment terms and accepted payment methods
A PDF attachment or a permanent link to the invoice
A simple, direct way to pay - ideally a payment link or button

When should you send an invoice?

Send the invoice as soon as the work is delivered or the milestone is reached - momentum matters, and a client is most willing to pay right after receiving value. For projects, consider invoicing a deposit up front and the balance on completion. We cover this in detail in when to send an invoice and payment terms for freelancers.

How to follow up on an unpaid invoice

If the due date passes, do not wait. A polite, prompt reminder is normal and expected. Send a friendly nudge the day after the due date, a firmer reminder a week later, and reference the original invoice number each time. Automated reminders make this effortless - the software sends them on schedule so you never have to write an awkward chase email. For wording and a full sequence, see how to follow up on late payment and consider adding late payment fees to your terms.

The easiest way to send an invoice

You can attach a PDF and write the email yourself - or let a tool handle it. With WaffleInvoice you send a professional invoice with a built-in payment link, and it tracks when the client opens it and pays, then sends reminders automatically if they do not. Create a free account to send your first invoice, or build one now with the free generator. Need a starting point? Browse free invoice templates first.

Frequently asked questions

What is the best way to send an invoice? Sending it with an online payment link gets you paid fastest, because the client can pay immediately instead of arranging a transfer separately.

Should I attach a PDF or paste the invoice in the email? Always send a PDF or a permanent link. Pasting numbers into the email body looks unprofessional and is easy for the client to lose track of.

How soon should I send an invoice? As soon as the work or milestone is complete. The sooner the invoice arrives, the sooner it gets paid.

How to Send an Invoice (And Get Paid Faster)