How to Write a Freelance Invoice: What to Include, Payment Terms, and Mistakes That Delay Payment

A step-by-step guide to writing a freelance invoice that gets paid on time: the details every invoice needs, how to word payment terms, and the mistakes that slow clients down.

By freelydesk, November 2, 20266 min read

The short answer

A freelance invoice needs your details, your client's details, a unique invoice number, the issue date and due date, itemized work with rates and a total, and clear payment terms with instructions for how to pay. Send it as a PDF as soon as the work or milestone is done, then track it until it's paid and follow up on the day it falls overdue.

What every freelance invoice needs

An invoice is a request for payment, but it is also a record. Your client's accounts team will file it, your accountant will need it at tax time, and you will look it up when someone asks what a payment was for. That is why the details matter more than the design.

Before you send anything, check that the invoice has each of these:

Your name or business name, address, and email.
Your client's name, company, and billing address, or the contact the invoice should go to.
A unique invoice number that you never reuse.
The issue date and a due date.
Line items that describe the work, with hours and rate or a fixed fee for each.
A subtotal, any tax that applies, and the total due, in one stated currency.
Payment terms and instructions: how to pay, and where to send it.

Step 1: Put both parties at the top

Start with who the invoice is from and who it is to. Use your legal or registered business name if you have one, plus an email address the client can reply to. If you are registered for tax, add your tax or VAT number here too.

For the client, use the name of the company that is paying, not just the person you work with. Larger clients often route invoices to an accounts payable inbox, so ask at the start of the project who should receive them and whether they need a purchase order number on the invoice. A missing PO number is one of the most common reasons an invoice sits unpaid.

Step 2: Number and date every invoice

Every invoice needs a unique number. A simple running sequence such as INV-0001, INV-0002 works well, and it makes gaps or duplicates easy to spot. Some freelancers add the year or a client code, which is fine as long as each number only ever appears once.

Add the issue date and the due date. Writing the actual due date is clearer than only writing the terms, because "due 14 November" leaves nothing to work out.

Step 3: List the work as clear line items

Line items tell the client what they are paying for. Describe each one in words the client would recognize, not internal shorthand: "Homepage design, two rounds of revisions" is better than "Design v2".

If you bill by the hour, show the hours and the hourly rate for each item. If you bill per project or per milestone, show the fixed fee and name the milestone. Either way, the client should be able to match every line to work they remember approving.

When you track time against the project as you work, this step is quick: the hours are already there, and you are not reconstructing a month from memory and calendar entries.

Step 4: Add totals and any tax

Show a subtotal, then any tax, then the total due. State the currency, especially for international clients, so nobody has to guess whether 1,500 means dollars, euros, or pounds.

Whether you charge sales tax or VAT depends on where you and your client are, what you sell, and how much you earn. Rules differ a lot by country, so check with your local tax office or an accountant before adding or leaving out tax. If you are not registered, do not add tax to the invoice.

Step 5: Write payment terms clients can follow

Payment terms tell the client when to pay and how. Common terms are due on receipt, 7 days, 14 days, or 30 days from the invoice date. Shorter terms usually get you paid sooner; larger companies often have fixed payment runs and may ask for 30 days.

Spell out how to pay: bank transfer details, a payment link, or another method you accept, plus the reference you want used, usually the invoice number. If you charge late fees, say so on the invoice and in your contract, and check that they are allowed where you work.

Because this text is nearly identical on every invoice, save it once and reuse it. A few saved notes, such as payment terms, bank details, and a thank-you line, keep every invoice consistent and stop you from forgetting a detail.

"Payment is due within 14 days of the invoice date."
"Please pay by bank transfer and use the invoice number as the reference."
"Invoices unpaid after 30 days may be charged a late fee, as set out in our agreement."

Step 6: Send it, then track it until it's paid

Send the invoice as a PDF as soon as the work or milestone is done. The longer you wait, the less urgent it feels to the client. Put the invoice number and due date in the email subject line so it is easy to find.

Then keep track of where each invoice stands: draft, sent, paid, or overdue. When an invoice passes its due date, follow up the same day with a short, friendly reminder and the PDF attached again. Most late payments are forgotten, not refused.

Clients also pay faster when they can see the invoice next to the work it covers. A client portal that shows the project's progress and its invoices in one place answers the "what is this for?" question before it gets asked.

See how invoices work in freelydesk

Mistakes that delay payment

Most slow payments come from small, avoidable gaps. Check for these before you press send:

No due date, or terms the client has to calculate.
Sending to your contact instead of the accounts team that actually pays.
Missing a purchase order number the client asked for.
Vague line items that the client can't match to approved work.
Payment details that are missing, out of date, or only in an old email.
Waiting weeks after the work is done to send the invoice.
Reusing or skipping invoice numbers, which confuses everyone's records.

Write invoices faster in freelydesk

freelydesk keeps each invoice attached to its project, with your tracked hours beside it. Every invoice has line items, a due date, and a status of draft, sent, paid, or overdue, and exports to a clean PDF, so you can see at a glance what is still owed.

On Pro, saved notes fill in your payment terms and bank details in one click, and your client sees the project and its invoices through one private portal link, so they always know what they are paying for. Plans start at $4.99 a month, with a 7-day free trial and no card required.

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Frequently asked questions

How do I write my first invoice as a freelancer?

Put your details and your client's details at the top, give the invoice a unique number, add the issue and due dates, list the work as line items with hours and rate or a fixed fee, show the total and currency, and finish with payment terms and how to pay. Send it as a PDF as soon as the work is done.

What payment terms should a freelancer use?

Many freelancers use 7 or 14 days from the invoice date, which gets money in faster than 30 days. Larger companies often pay on 30-day cycles, so agree on terms before the project starts and put them in your contract and on every invoice.

Should I invoice hourly or per project?

Either works on an invoice. Hourly invoices list hours and rate per line item; project invoices list a fixed fee per milestone or deliverable. Choose the one that matches your agreement with the client, and keep the line items specific enough that the client recognizes each one.

Can I ask for a deposit before starting work?

Yes. Many freelancers invoice a deposit, often a share of the project fee, before work begins, then invoice the rest at milestones or on delivery. Send the deposit as its own numbered invoice so your records stay clear.

What should I do when a client pays late?

Send a polite reminder on the day the invoice becomes overdue, with the invoice attached again and the payment details repeated. If it is still unpaid a week later, follow up again and mention any late fee from your agreement. Most late invoices are paid after a clear reminder.

Do I need to charge sales tax or VAT on freelance invoices?

It depends on your country, your client's location, what you sell, and how much you earn. Check with your local tax office or an accountant. If you are not registered for sales tax or VAT, do not add it to your invoices.