The complete guide to invoicing for freelancers & small businesses

A clear invoice removes friction. The faster your client can confirm what they owe and why, the faster you get paid. At a minimum, every invoice should contain:

• The word "Invoice" (or "Quote", "Credit Note", etc.) so it's instantly recognisable.
• A unique invoice number for your records and theirs.
• Issue date and a clear due date.
• Your business name, address, and contact details.
• Your client's name and address.
• A line-item description of goods or services with quantity, rate, and amount.
• Subtotal, tax, discounts, shipping, and total due — broken down clearly.
• Accepted payment methods and any relevant bank details or links.
• Your tax / company registration numbers if applicable (e.g. VAT ID, Company No).

If you sell internationally, also include the currencynext to amounts — "$1,200" is ambiguous if your client is in Singapore. You can switch currency in one click inside our free invoice generator.

These three documents look similar but serve very different purposes:

• Quote (or estimate): a non-binding offer given before work starts. It tells the client "here's what this will cost".
• Invoice: a legally binding request for payment, sent after delivery (or per a milestone schedule). It says "this is what you owe, and when".
• Receipt: proof that payment has been received. Sent after the invoice is paid.

A credit note is essentially a "negative invoice" — used when you refund a client or correct an overcharge.

Invoice numbers need to be unique and sequential. Most tax authorities require this for audit purposes. Common conventions:

• INV-0001, INV-0002, INV-0003 — simple and clean.
• 2026-001, 2026-002 — year-prefixed for easier filing.
• ACME-2026-001 — when you want client codes baked in.

Pick a scheme and stick with it. Never re-use a number, even for a voided invoice — issue a credit note instead. Our invoice maker supports invoices, quotes, and credit notes from the same screen.

The most common payment terms you'll see and use:

• Due on receipt: payment is expected immediately. Common for one-off small jobs and retail.
• Net 7 / Net 15: due 7 or 15 days after the invoice date. Good for projects with shorter cycles.
• Net 30: the corporate default. Due 30 days after the invoice date.
• Net 60 / 90: common in enterprise contracts. Negotiate hard before agreeing — it impacts your cash flow.

It's also normal to charge a late fee (e.g. 1.5% per month on overdue balances). Mention it in the terms section of your invoice so clients see it before things go late.

Where these adjustments sit affects the final total — and clients will check. Show your maths.

Tax

Apply tax (VAT, GST, sales tax) as a percentage of the subtotal. Show the rate and the amount separately so your client can verify it. If you're not registered for tax, leave it off and (in some jurisdictions) add a note explaining why.

Discounts

Discounts can be a flat amount ("£100 off") or a percentage ("10% off"). Apply them before tax so the tax base reflects the discounted amount, unless your jurisdiction says otherwise.

Shipping

Shipping is usually a flat add-on after the subtotal. Whether shipping is taxable depends on where you operate — check local rules.

The simplest order is: Subtotal → minus Discount → plus Tax → plus Shipping → Total.

1. Send invoices the moment work is done. Every day you delay sending adds days to when you're paid.
2. Make the due date specific. "Due March 28, 2026" beats "Net 30" — there's no maths for the client to do.
3. Offer multiple payment methods. Bank transfer is fine, but adding a payment link (Stripe, PayPal, Wise) removes friction.
4. Send polite reminders. One a few days before due, one on the day, one a week after. Keep them friendly — most late payments are accidents, not intent.
5. Charge a deposit on larger projects. 30–50% up front protects your cash flow and filters out non-serious clients.
6. Use clear, consistent branding. Invoices that look professional get paid faster — they look real, not improvised.