How to Make a Simple Invoice

If you’ve ever done freelance work, sold a service, or been paid on the side, you’ve probably sent an invoice — and if you did it in a word processor, you probably missed something important. A professional invoice takes less than ten minutes to assemble, pays faster than a casual email, and creates the paper trail your tax return will thank you for in April.

This guide covers what a simple invoice needs to include, what to leave out, how to set payment terms that actually get you paid, and the small polish that makes your invoice look like it came from a real business — because it did.

What every invoice must include

At minimum: the word “Invoice,” a unique invoice number, the issue date, your business name and contact details, your client’s name and contact details, a line-item list of what you’re billing for, the subtotal, any tax, the total due, and payment instructions. Skip any of these and your client’s accounts-payable team will bounce it back with questions — which delays your payment by a week.

Number your invoices sequentially

Start at 001 (or 1001 if you don’t want your first client to know they’re your first) and increment. Never reuse a number. If a tax authority ever asks to see your records, sequential numbering is the first thing they look for — gaps or duplicates look like something is hidden. Our invoice generator handles this automatically if you let it.

Set payment terms that match the job

The default “Net 30” (pay within 30 days) is a holdover from corporate accounting departments. For small clients, Net 7 or Net 14 is more reasonable and gets you paid faster. For large projects, a 50% upfront deposit plus 50% on delivery is normal. Write the terms clearly on the invoice — “Payment due within 14 days of issue” — and include the exact due date so nobody has to do the math.

Describe work in detail

“Consulting, $2,000” is a weak line item — it looks arbitrary to a finance reviewer and invites negotiation. “Landing page design, 12 hours × $85/hr = $1,020” is specific. Break the work into 2–6 line items with quantity, unit price, and description. Figure out your number with our freelance rate calculator or hourly rate calculator if you’re setting a rate for the first time.

Handle taxes correctly

Tax rules vary by country and by how you’re registered. In the US, sole proprietors often don’t charge sales tax on services but may on goods — check your state. In the UK and EU, VAT depends on whether you’re registered and where your client is. List the tax on its own line with the rate, never bury it in the line item. If you’re not charging tax, a line that says “Tax: $0.00” beats omitting the line entirely — it answers the question before it’s asked.

Include multiple payment options

The easier you make it to pay, the faster you get paid. At minimum: bank transfer details (or a payment link), and for international clients, a platform option like Wise or PayPal. For US domestic, Zelle, ACH, or a simple Stripe invoice link work well. Include clear instructions — account number, routing number, reference/memo field to put your invoice number in.

Record what was delivered

A one-line project note (“Delivered via Dropbox on 22 April 2026 — 12 files”) closes the loop and creates a record. This matters if there’s ever a dispute six months later about whether work was actually completed.

Send it as a PDF, not a Word doc

A PDF is frozen — the client can’t accidentally (or intentionally) edit the amount. Word docs get reformatted on the receiver’s machine and look unprofessional half the time. Generate the PDF once, attach it to a short email, and keep a copy in a folder organized by year.

Follow up politely and on schedule

Most unpaid invoices are just forgotten, not refused. Send a friendly reminder two days before the due date, another on the due date, and a firmer note seven days past due. Keep the tone professional — the client who is late this quarter is often the one who pays best the next. Use our deadline calculator to track when each invoice crosses each threshold.

Keep records for at least five years

Tax authorities in most countries can audit up to five or seven years back. Save every invoice you’ve sent — PDF is fine — in a clearly named folder. At year-end, this file is 80% of your income documentation.

Template, don’t reinvent

Don’t rebuild the invoice from scratch every time. Save one clean template with your business details, logo, and payment instructions. For each job, you just update the invoice number, client, line items, and total. Our invoice generator produces a print-ready version in under a minute.

Related: how to price freelance work, how to save on taxes, and how to calculate profit margin so you know what each invoice actually earns you after costs.