An invoice is a request for payment that states who is asking, who owes, what was delivered, how much it costs and how to pay. Making one is not hard, but a sloppy invoice is the most common reason a payment stalls: a missing bank detail, an unclear description or a due date nobody agreed to.
This guide walks through the whole process from an empty page to a PDF in the client's inbox. The steps are tool-agnostic; where it helps, we show how each one works in Simple Invoice, a free invoice generator that runs entirely in your browser with no account.
Before you start: gather five things
You can write an invoice in a few minutes if the inputs are ready. Collect these first, and keep them somewhere you can reuse them — a good invoicing tool stores them once and fills them in for you.
- Your business details — legal or trading name, address, email, and any tax or registration id you are required to show.
- The client's details — the exact legal entity to bill, their address, and the name or email of the person who approves payment.
- What you delivered — a list of services or goods with quantities and agreed rates, ideally lifted from the quote or contract.
- How you want to be paid — bank account or IBAN, BIC/SWIFT, or the payment service the client agreed to use.
- The terms — how many days the client has to pay and what happens if they do not. Agree these before the work, not on the invoice.
Step 1 — Set up your business profile once
Every invoice needs the same From block. In Simple Invoice, type your name, address, email and tax id directly into the From block on the document.
The logo lives on the header. Click the upload square, pick a PNG, JPEG, WebP or SVG, and it is stored in this browser for the current document. How to add a logo to an invoice covers sizing and formats.
Set your defaults at the same time: currency, due period, the taxes you usually charge, the payment details block and any standard notes or terms. New invoices start from these values, which removes most of the typing from steps 5 and 6.
Step 2 — Choose a template that fits the work
A template decides which blocks appear and how they look. Pick one that matches the kind of work you bill for rather than the prettiest one: hourly work wants a dense table with a unit column, a consulting retainer wants fewer lines with room to describe a milestone, a contractor invoice wants terms and a signature line. The template gallery describes each preset and who it suits.
Simple Invoice ships ten built-in presets. Switch between them in the Template section; if a document is already open, the editor asks before replacing it. Once you have adjusted colours, fonts or blocks you can save the result as your own template.
Step 3 — Add the client
Bill the legal entity that signed the agreement, spelled the way it appears on their paperwork. Large companies often need a purchase order number or a cost centre on the invoice before accounts payable will process it — ask before you send rather than after it bounces.
Type the client's details into the Bill To block on the invoice. There is no separate client list — each document is filled in by hand.
Step 4 — Add line items
Each line item answers three questions: what was done, how much of it, and at what rate. Write descriptions the client's finance team can match to the quote or contract — "Website redesign — phase 2, homepage and navigation" beats "Design work". If a line needs context, put it in a secondary details line rather than lengthening the description.
Quantities can be fractional (7.5 hours) and can carry a unit — hours, days, items, m². The amount per line is quantity multiplied by rate, rounded to the currency's decimals, and the subtotal is the sum of the lines. Simple Invoice computes these live as you type; press Enter in the last field to add the next row and drag the handle to reorder.
- One deliverable per line. Bundling everything into a single line invites a query.
- Match the order of the quote so the client can tick items off.
- Use the same units and rates you agreed. If something changed, say so in the notes.
Step 5 — Apply taxes and discounts
Whether you must charge tax, at what rate and how it must be shown depends on where you and your client are and on your registration status. That is a question for your accountant or tax authority — our tax basics guide explains the moving parts without giving advice.
Mechanically, an invoicing tool needs to know two things: which lines are taxable and which taxes apply. Simple Invoice lets you add any number of taxes with a label and a rate; each is calculated on the taxable lines after discounts and shown separately in the totals block. Discounts can be per line (a percentage or a fixed amount) or applied to the whole invoice before tax.
If you have already received a deposit, enter it as Amount paid. The totals block then shows the total, the amount paid and the balance due, which is the figure the client should transfer.
Step 6 — Payment details and terms
The payment details block is where the money actually gets routed. Include every identifier the client's bank will ask for: account holder name, IBAN or account number, BIC/SWIFT for international transfers, bank name and, if you accept it, a payment service address. Check these characters twice; a transposed digit is the slowest mistake to recover from.
Terms state when payment is due and under what conditions. "Due within 14 days of the invoice date" is clearer than "Net 14". If you charge late fees or offer an early-payment discount, this is where it goes. Invoice payment terms explained covers the common options and how to word them.
In Simple Invoice both are blocks: the payment block renders a key/value list from your defaults, and the terms block prints the invoice's terms text. Toggle either off for clients who pay by card link and do not need bank details on paper.
Step 7 — Number and date the invoice
Every invoice needs a unique, sequential number and an issue date. Many jurisdictions require the sequence to be unbroken, and your client's system will reject a duplicate. Decide on a pattern once — a prefix, an optional year and a zero-padded counter such as INV-2026-0042 — and let the tool increment it. Invoice numbering best practices goes deeper.
The due date follows from the issue date and your terms. Simple Invoice fills it in from your default due period and lets you adjust it; it also keeps a place-of-issue field, a reference and a PO number for clients who need them.
Step 8 — Review, then export a PDF
Read the invoice as the payer will. Is the total unmistakable? Are your bank details complete? Is the client name exactly right? Does the description match the quote? Switch to preview mode to see the document without editing chrome, and check the page breaks if the item table is long.
Then export. Simple Invoice produces the PDF through your browser's print dialog: choose Export → PDF, pick Save as PDF as the destination and keep margins on None with background graphics on. The paper size — A4 or Letter — is set from the template automatically in most browsers. The result is a small, vector PDF with real text that finance systems can search and read.
You can also copy a share link. The whole invoice is compressed into the part of the URL after #, which browsers never send to a server; the recipient opens a read-only view in their browser and can save a copy if they use the app too.
Step 9 — Send it and track it
Send the PDF as an attachment with a short, specific subject line: "Invoice INV-0042 — Website redesign phase 2 — due 26 Sep". Put the amount, due date and the invoice number in the body so the recipient does not have to open the file to file it.
Simple Invoice does not track draft, sent, paid or overdue statuses, so record the due date and payment in your own spreadsheet or accounting tool. If payment does not arrive, these reminder templates give you polite, escalating wording.
Common mistakes that delay payment
Late payments usually trace back to one of these. Check for them before you press send.
- Wrong entity. Billing the person you spoke to instead of the company that contracted you.
- Missing PO number. Large clients cannot pay without it, and their system will not tell you.
- Vague descriptions. Anything the approver cannot match to an agreement gets queried.
- Incomplete bank details. No BIC on an international transfer, or an account name that does not match the bank's record.
- No due date. "Payable on receipt" without a date gives the client nothing to schedule against.
- Duplicate or edited numbers. Reused numbers get rejected as duplicates; edited ones break your own audit trail.
Next steps
Once you have made one invoice, keep its PDF or JSON file, then reuse the editor's sidebar choices for the next document. Update the client, number, dates and line items before exporting again. How to invoice as a freelancer covers the routine around invoicing: deposits, milestones, retainers and record keeping.
Questions
Can I make an invoice for free?
Yes. Simple Invoice is free with every feature included and no account. It runs in your browser, stores data locally and exports PDFs through the print dialog. The FAQ explains how that works in practice.
What makes an invoice valid?
Requirements vary by country and by whether you are registered for VAT, GST or sales tax. In general an invoice needs the word invoice, a unique number, dates, both parties' details, a description, amounts and any applicable taxes. What to include on an invoice lists each element; confirm specifics with your tax authority.
Should I make invoices in Word or Excel instead?
A word processor or spreadsheet works for a handful of invoices, but numbering, totals and consistent layout are manual. Invoice generator vs Word template and vs Excel template weigh the options honestly.
How do I turn the invoice into a PDF?
Use Export → PDF, choose Save as PDF in the print dialog, and keep margins at None with background graphics on. The paper size is preselected to match the template in Chrome, Edge and Firefox; in Safari set it manually.