Sending an invoice sounds simple until you're staring at a blank document wondering what to include, how to word the email, and why the client hasn't responded in two weeks.
This guide covers the full process — what goes on the invoice, how to send it, how to write the follow-up, and what happens when it goes unpaid.
What to Include on the Invoice
Before you send anything, make sure the invoice itself has everything it needs.
Your information: Your name or business name, address, email, and phone number. If you have an LLC or EIN, include those too.
Client information: The client's full legal name, business name, and address. Not just their email.
Invoice number: A unique identifier you can reference in all follow-up. Use a simple system: year + sequential number (2026-001, 2026-002) or project-based.
Invoice date: The date you're sending it.
Payment due date: An explicit date — not "net 30" without a start date. "Due July 15, 2026" is clearer than "net 30" and gets paid faster.
Itemized services: A clear breakdown of what you did, not a single line for the total. "Brand strategy session, 2 hrs" and "Logo design, 3 concepts + 2 revisions" is better than "design work."
Total amount due: Bold, prominent, impossible to miss.
Payment methods: List every way the client can pay, with the details they need to do it. The easier it is to pay, the faster you get paid.
Late fee policy: "A 1.5% monthly fee applies to balances unpaid after [due date]." Putting this on the invoice — not buried in your contract — creates the urgency that gets it prioritized.
How to Send the Invoice
Format
Send as a PDF. Not a Word doc, not a Google Sheets link, not a screenshot.
A PDF is non-editable, looks professional, and can be forwarded to accounts payable without losing formatting.
Email or Invoicing Software
Dedicated invoicing software is the most professional approach. Platforms that send invoices via email also give the client a payment link — clients pay directly on the invoice, and you're notified immediately. No back-and-forth, no "I never got it."
Email with a PDF attachment works fine for straightforward situations. Attach the PDF, write a short professional email, and send to the right person.
The wrong approaches: texting an invoice, sending it on Instagram DM, or sharing a payment link with no formal invoice attached. These make follow-up harder and look unprofessional to clients running an actual business.
Send to the Right Person
"The client" is not always the right recipient. For corporate clients, find out who handles accounts payable — it may not be your contact.
Ask upfront: "Who should I address invoices to?" It sounds like a small thing, but invoices sent to the wrong person at a company can sit in someone's inbox for weeks.
Include a PO Number if Required
Many corporate clients require a purchase order (PO) number on every invoice before they can process payment. Ask for it before you deliver work. An invoice without a required PO can sit in limbo indefinitely.
How to Write the Invoice Email
Keep it short. This isn't the place for a project recap or a thank-you speech.
Subject: Invoice #2026-041 — [Brief Project Description]
Body:
Hi [Name],
Please find attached Invoice #2026-041 for [brief description, e.g., "the Q2 brand identity project"], due on [due date].
[Payment link or "Payment instructions are included on the invoice."]
Let me know if you have any questions.
[Your name]
That's it. One paragraph. The invoice has the details — the email just delivers it.
If you're sending a balance invoice after collecting a deposit, note it briefly: "This covers the remaining balance following the retainer paid on [date]."
When to Send the Invoice
For project work: Send the final invoice at delivery — the moment you send the completed files or deliverables. Don't wait a week. Don't send it the day before and forget.
For retainers: Send the invoice on the same day every month, before the month begins. Retainers paid in advance are the professional standard.
For event-based work (photography, videography): Send the balance invoice 2–4 weeks before the event, due before the date. Never arrive at an event without having received full payment.
For milestone-based projects: Set invoice dates at the start of the project so both parties know what's coming and when.
How to Follow Up When an Invoice Goes Unpaid
Consistent, professional follow-up gets invoices paid. Here's the sequence:
Day after due date: A short, friendly reminder.
"Hi [Name] — just a quick note that Invoice #2026-041 was due yesterday. Please let me know if you have any questions or need anything on my end."
5 days overdue: A follow-up with the late fee mentioned.
"Following up on Invoice #2026-041, now 5 days past due. Per our agreement, a late fee of 1.5% per month has begun accruing on the outstanding balance. Please let me know if there's a hold-up on your end."
14 days overdue: Firmer language, final deadline.
"Invoice #2026-041 remains unpaid at 14 days overdue. The current balance including late fees is $[amount]. I need this resolved by [date] — please confirm you've received this and when to expect payment."
30 days overdue: Formal demand. At this point, consider a demand letter, small claims court (for amounts under your state's threshold), or a collections agency.
The key throughout: always reference the invoice number, always state the current balance (including any late fees), always give a specific deadline.
The Fastest Way to Get Paid
A few things consistently speed up payment:
A direct payment link on the invoice. Clients who can click "Pay Now" pay faster than clients who have to initiate a bank transfer.
Shorter payment terms. Net 7 or net 14 gets paid faster than net 30, especially for smaller amounts. Reserve net 30 for corporate clients who require it.
Automated reminders. Following up manually is easy to forget. Tools like FileCurrent send payment reminders automatically — before the due date, on it, and every day after — so overdue invoices get chased without you having to think about it.
Invoice immediately. The longer you wait to send an invoice after delivery, the longer you wait to get paid.
What to Do When a Client Refuses to Pay
First, confirm the dispute in writing. Ask directly: "Can you let me know what's preventing payment on Invoice #2026-041?"
If it's a scope dispute — they claim you didn't deliver what was agreed — your contract and project communications are your evidence. A signed contract plus email sign-offs on deliverables is a strong paper trail.
If they just don't respond or keep stalling:
Small claims court:: Available for amounts under your state's limit (typically $5,000–$10,000). Filing is inexpensive and the process is straightforward for documented cases.
Demand letter:: A formal letter (sometimes from an attorney) stating the amount owed and a final payment deadline.
Collections agency:: Takes 25–40% of the recovered amount, but handles the follow-up for you.
Prevention is better than recovery. A signed contract with clear payment terms and a documented delivery process is what makes any of these options viable.
Frequently Asked Questions
How do I send an invoice to a client for the first time?
Create a professional invoice with your information, the client's information, an invoice number, the due date, an itemized breakdown of services, and your payment methods. Send as a PDF via email with a short, professional message. Ask upfront who handles invoices for corporate clients, and confirm whether they need a PO number.
What should I write in an invoice email?
Keep it brief: a subject line with the invoice number and project name, one sentence describing what the invoice covers, the due date, and a payment link or note that instructions are on the invoice. That's all. The details are on the invoice itself.
When is the right time to send an invoice?
For project work, immediately at delivery. For retainers, before the month begins. For event photography or videography, the balance invoice should be paid before the event date. Don't delay — the sooner you send it, the sooner it enters the client's payment queue.
What if my client says they didn't receive the invoice?
Resend it, reference the original date, and ask them to confirm receipt. Going forward, use invoicing software that tracks when an invoice is opened — it removes the "I never got it" response from the conversation.
How do I politely follow up on an overdue invoice?
Reference the invoice number and due date, state the current balance (including any late fees), and give a specific next deadline. Keep the tone professional, not apologetic. You did the work; they owe you the payment.
The Bottom Line
Sending an invoice isn't complicated — but doing it consistently, professionally, and with the right follow-up is what separates freelancers who chase payments from freelancers who get paid on time.
Send it the day you deliver the work. Make it easy to pay. Follow up without hesitation.
If you want reminders to run automatically so you never have to manually chase a late invoice, FileCurrent handles that for you — 7-day trial, no card required. For a related guide, see our photography invoice template for how to structure invoices by project type.
This article is for informational purposes only and does not constitute legal or financial advice.