How to do an invoice for free, step by step

How do you do an invoice?

To do an invoice, put your details and your customer's at the top, give it a number you have never used, list the work with a price on each line, then add the total, the due date and how to pay. Save it as a PDF and send it. In Invoice Koi's free browser generator that takes a few minutes, with no account and nothing to install.

If you need a document now, start a free invoice here. If you want to check the format first, use our worked invoice example. The steps below take a small repair job from blank form to a file you can attach to an email.

A free PDF and a free payment are different things. Making this document costs nothing. A bank, card processor or other payment provider may charge for the method you agree with your customer, and writing payment details on a PDF does not set up payment processing.

What is an invoice, and when do you send one?

An invoice is the document that asks a customer to pay for work you have done or goods you have supplied. You send it when the job is finished, or at the stage you agreed, and it stays the record of what was owed.

It is not an estimate, which is a price before the work and asks for nothing. It is not a receipt either, which confirms that the money arrived. One job can have all three: the estimate the customer said yes to, the invoice when the work is done, and the receipt when they pay.

You do not need a company to send one. You can invoice in your own name, and what that invoice needs is in the independent contractor invoice guide.

What do you need before you start?

The customer's billing name and address, a description of the job, the agreed price and the date you want to be paid. Everything else on the invoice is yours.

If the customer is a business, ask whether accounts payable needs a purchase order number or a particular billing address. Put any reference they give you in the notes, so the person approving payment can match it to the job.

What is an invoice number?

It is the reference that makes this invoice different from every other one you send. Your customer quotes it when they pay, and you use it to match the payment to the job.

Any scheme works if it only goes up and never repeats: INV-0001 then INV-0002, or a year in front, like INV-2026-014. The generator starts at INV-0001 and does not remember your last number, so type the next one in your own sequence. The app keeps count for you.

Two dates and a currency

Keep the invoice date separate from the date the work was done. Write the due date in full: September 30, 2026 is easier to act on than a term the customer has to work out.

Use the currency you agreed. An invoice for $185.00 USD should not leave an overseas customer guessing which dollar or pound you mean. Tax depends on your circumstances, so do not copy a tax setting from an example without checking it.

Enter the work as two clear line items

For this fictional repair, enter two hours of labor at $75.00 per hour and one replacement part at $35.00. The first line is $150.00, the second is $35.00, and the subtotal is $185.00. These figures demonstrate the calculation, not a suggested price for your trade.

Use a description such as “Adjust sticking internal door and test closure” instead of “Work done”. Add the service date and job reference in the description or notes. The customer should be able to recognize the work without opening an old message thread.

This example assumes no tax is chargeable and no discount or earlier payment applies, so the amount due is $185.00. Replace those assumptions with your own treatment. If you have already received part of the price, make the remaining balance explicit rather than asking the customer to subtract it mentally.

Save the invoice as a PDF and open it

In the generator, select Download PDF. This opens your browser's print controls. On desktop Chrome, choose Save as PDF as the destination, inspect the preview, then save the file. Other browsers and phones may present different print or share controls. Google's Chrome printing instructions explain where those controls live.

Check the US Letter paper setting and every page of the preview. If the browser adds a web address or date around the invoice, turn off its headers and footers. Avoid reducing the scale so far that a customer has to zoom in to read the payment details.

Name the file INV-2026-014.pdf, then open the actual saved file. Check the customer, invoice number, amount due and payment instructions. A preview is useful; the attachment is what the customer will receive.

How do you send an invoice?

Attach the PDF to an email from your own address, with the invoice number, the amount and the due date in the message. Then keep a copy of the PDF where you can find it again.

Our invoice email templates have the wording to copy, including a short message for a customer who would rather get the invoice by text or WhatsApp. The generator does not send the document for you or tell you when a customer has paid it.

The generator saves its current draft in this browser when browser storage is available. That is a convenience, not an invoice archive. Clearing site data, using private browsing or moving to another device can leave you without that draft, so save each finished PDF somewhere you back up.

Keep the invoice with your business records. The IRS recordkeeping guide includes invoices among supporting documents. That guidance concerns records, not a universal US invoice format or sales-tax rule.

Should you use QuickBooks, Xero or PayPal instead?

If you already keep your books in QuickBooks or Xero, do your invoices there, because an invoice raised inside your accounts is already in your accounts. If you do not, you do not need accounting software to send one.

That is why so many people search for these by name: they already have the software and want the button. Both raise the invoice in the same ledger as your income and expenses, so nobody types it in twice, and that is worth more than any template once somebody does your accounts from the same file.

PayPal and Stripe come at it from the other end. Their invoice is a way to get paid through them: the customer pays from a link, and the service takes a fee from what arrives. Check that fee on their own pages before you choose, because it changes.

A free generator is the opposite trade. There is nothing to set up and nothing to pay, and nothing follows up either. It suits a one off job, the first few invoices, or anybody whose books are a folder of PDFs.

The Invoice Koi app sits between them, for the person who invoices from the job rather than from a desk. It is free to set up and draft in and needs a subscription to send, and the comparison pages set it beside the other invoicing apps. Whether you need accounting software at all is a question for whoever does your books.

The quick answers