How to Make an Invoice: The Complete Guide
An invoice is a request for payment: a document listing what you supplied, what it costs, when payment is due and how to pay. To make one, you need your details and your client's, a unique invoice number, the date and due date, an itemized list with prices, any tax, and the total. This guide covers what to include, how invoices differ from receipts and quotes, payment terms like Net 30, numbering, and how to get paid on time.
What to include on an invoice
A professional invoice answers every question the person paying it will have, so it never needs a follow-up email. These are the elements to include — the first group appears on virtually every invoice, and several become legal requirements once you're registered for VAT or GST:
| Element | Why it matters |
|---|---|
| The word "Invoice" | Makes clear this is a payment request, not a quote or receipt. |
| Unique invoice number | Lets both sides reference, track and reconcile the payment. Required to be sequential under EU VAT rules. |
| Your business name and contact details | Who is being paid, and how to reach you with questions. |
| Client name and address | Who owes the money — and for business clients, who their accounts team should file it under. |
| Issue date and due date | Starts the payment clock and states exactly when payment is expected. |
| Itemized products or services | A description, quantity, rate and line total for each item, so the charge is easy to check. |
| Subtotal, discount, tax and total | Shows exactly how the amount due was calculated, including the tax rate applied. |
| Payment terms and methods | Terms like Net 30, plus bank details or a payment link — the single biggest factor in getting paid quickly. |
| Tax or VAT number | Required on VAT invoices in the EU and UK once you're VAT-registered. |
| PO number (if given one) | Many larger clients can't approve payment without their own purchase order reference. |
Frost Rank's free Invoice Generator has a field for every element above, lays them out in a clean invoice template, and exports a PDF — with no signup and no watermark.
How to make an invoice, step by step
1. Add your business details. Your business (or personal) name, email, phone, address, logo, and tax or VAT number if you're registered.
2. Add the client's details. Their name or company name and billing address. For businesses, use the accounts payable email if you have it — it's often not the person who hired you.
3. Assign an invoice number and dates. Use the next number in your sequence, the date you're issuing it, and the due date based on your payment terms.
4. List what you're billing for. One line per product or service, with a clear description, quantity (or hours) and rate. Vague lines like "services rendered" are a common reason invoices get queried and paid late.
5. Apply discounts, tax and shipping. Take any discount off the subtotal first, then calculate tax on the discounted amount, then add shipping.
6. Explain how to pay. Bank details, a payment link, or both — and the reference you'd like them to use (usually the invoice number).
7. Send it as a PDF and keep a copy. A PDF can't be accidentally edited and looks the same on every device. Save your own copy with the same number.
Invoice vs. receipt vs. quote vs. proforma invoice
These four documents look similar but do different jobs, and sending the wrong one causes confusion in the client's accounts department:
| Document | When it's sent | What it means |
|---|---|---|
| Quote / estimate | Before any work is agreed | A proposed price the client can accept or decline. |
| Proforma invoice | After agreement, before delivery | A preliminary bill in invoice format — not a demand for payment and not recorded as money owed. Common in international trade. |
| Invoice | After delivery (or at an agreed milestone) | A formal request for payment, recorded as money owed. |
| Receipt | After payment | Proof that the payment was received. |
If an invoice turns out to be wrong after you've sent it, don't delete it or reuse its number — issue a credit note that cancels it (fully or partly) and send a corrected invoice with a new number. That keeps your numbering sequence and records intact.
Payment terms explained: Net 30, due on receipt and 2/10 Net 30
| Term | What it means |
|---|---|
| Due on receipt | Payment is expected as soon as the invoice arrives. |
| Net 7 / Net 15 | Full payment due 7 or 15 days after the invoice date — common for freelancers and small jobs. |
| Net 30 | Full payment due 30 days after the invoice date — the most common term for business clients. |
| Net 60 | Full payment due in 60 days — often requested by large companies. |
| 2/10 Net 30 | A 2% discount if paid within 10 days; otherwise the full amount is due in 30. |
An early-payment discount like 2/10 Net 30 looks small, but it's a strong incentive. Using the example invoice from the Invoice Generator, with a $4,006.57 total:
Invoice total $4,006.57
Pay within 10 days (2% off): $4,006.57 − $80.13 = $3,926.44
Pay on day 30: $4,006.57
Cost to the buyer of skipping the discount:
2% ÷ 98% = 2.04% for 20 extra days
2.04% × (365 ÷ 20) ≈ 37.2% per yearGiving up 2% to keep the money 20 days longer is the equivalent of borrowing at about 37% a year, so a well-run finance team will usually pay early. For you, that means cash in 10 days instead of 30, at a cost of 2% of the invoice. Whatever terms you choose, state the exact due date on the invoice rather than only "Net 30" — a date leaves no room for interpretation.
How to number your invoices
Every invoice needs a unique number, and the numbers should follow a consistent sequence with no reuse. Under EU VAT rules, invoices must carry a sequential number that uniquely identifies them, and tax authorities elsewhere expect the same in practice. Common schemes:
| Scheme | Example | Good for |
|---|---|---|
| Simple sequence | INV-0001, INV-0002 | Most freelancers and small businesses. |
| Year prefix | 2026-0001, 2026-0002 | Seeing at a glance which year an invoice belongs to. |
| Client prefix | ACME-001, ACME-002 | Tracking many invoices per client — but keep numbers unique across all clients. |
Pad numbers with leading zeros (0001 rather than 1) so they sort correctly in file lists and spreadsheets. The Invoice Generator's "New invoice" button keeps your business details and moves to the next number automatically.
How to get paid on time
Invoice promptly. Send the invoice as soon as the work is delivered or the milestone is reached — every day of delay pushes the due date back too.
Make paying effortless. Include bank details and a payment link, state the reference to use, and send it to whoever actually pays (often accounts payable, not your day-to-day contact).
Ask for a deposit on larger jobs. Taking part of the fee upfront reduces your risk. Record it as "Amount already paid" so the invoice shows the remaining balance due.
Follow up on a schedule. A friendly reminder a few days before the due date, another on the day, and a firmer one a week after is a reasonable default. Late-payment laws can also help: in the UK, for example, businesses can claim statutory interest of 8% above the Bank of England base rate on late payments from other businesses.
Frequently asked questions
An invoice is a document a seller sends to a buyer requesting payment for goods or services already provided or agreed. It lists who is billing whom, a unique invoice number, the date, an itemized description of what was supplied with quantities and prices, any tax, the total amount due, the due date and how to pay. For the seller it records money owed (accounts receivable); for the buyer it is the basis for paying and for claiming back tax such as VAT where that applies.
An invoice asks for payment; a receipt confirms payment has been made. You send an invoice before you are paid (or to request the balance), and you issue a receipt afterward as proof the money was received. An invoice that has been paid in full can serve as a record of the sale, but it still is not a receipt unless it is marked as paid with the payment date.
A proforma invoice is a preliminary bill sent before goods are delivered or work is done — a detailed quote in invoice format. It tells the buyer exactly what they will be charged so they can arrange payment, approval or, in international trade, import paperwork. It is not a demand for payment and is not recorded as money owed; once the sale goes ahead you issue a normal invoice with its own invoice number.
"2/10 Net 30" means the buyer can take a 2% discount by paying within 10 days; otherwise the full amount is due within 30 days. On a $4,006.57 invoice, paying early saves $80.13. For the buyer, skipping that discount is expensive: giving up 2% to hold the money for 20 more days works out to roughly 37% a year in simple-interest terms, which is why many finance teams always take it.
In many countries, yes — freelancers and sole traders commonly invoice under their own name for services they provide, and an invoice doesn't require a company. What changes with registration are the obligations: once you are registered for VAT or GST, for example, your invoices must meet stricter content rules and show your tax number. Income from invoices is usually taxable either way, so check the rules for your country or ask an accountant.
It depends on your country, but plan for several years. In the US, the IRS generally recommends keeping records for three years from filing, and up to seven years in some situations; UK limited companies must normally keep records for six years. Save every invoice as a PDF and keep the original numbering sequence intact — Frost Rank's Invoice Generator can also save each invoice as a file you can reopen and edit later.
The totals and the 2/10 Net 30 figures in this guide were computed in code — the invoice example comes straight from Frost Rank's own Invoice Generator, which rounds every step to the cent — and the invoicing rules cited (EU sequential numbering, UK statutory late-payment interest) reflect the published requirements rather than rules of thumb.
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