What an invoice is and why you need one

An invoice is a written record that you send to someone who owes you money. It lists what they owe you for — whether that's work you did, goods you sold, or a service you provided — and how much they owe. The invoice also tells them when and how to pay you.

You need an invoice because it creates a paper trail. It protects both you and the person paying by making clear what was agreed to, what the cost is, and when payment is due. If there's ever a disagreement about what was owed or whether payment was made, the invoice is your proof.

Invoices are used in many situations: a plumber invoices a homeowner after fixing a pipe, a freelancer invoices a client after completing a project, a small business invoices another business for supplies. Even if you're just lending money to a friend or family member, an invoice can prevent misunderstandings.

Key Takeaways

  • An invoice must include your name and contact information, the other person's name, a description of what they owe you for, the amount due, and the date payment is due.
  • You can create an invoice by hand on paper, using a free template in Word or Google Docs, or with free invoicing software like Wave or Square Invoices.
  • Number your invoices in order so you can track them, and keep a copy for your own records before you send it.
  • The invoice should state how you want to be paid — cash, check, bank transfer, or another method — and where the payment should go.

The information that must go on an invoice

Start at the top with your name and contact information. Include your phone number and email address so the person paying knows how to reach you with questions. If you have a business name, put that at the top too.

Next, add the other person's name and address — the person or business that owes you money. Below that, write the date you created the invoice and the date payment is due. These are two different dates: the creation date is when you sent the invoice, and the due date is when you expect the money.

In the middle of the invoice, describe what the payment is for. If you did work, describe the work and the dates you did it. If you're selling something, list what it is. Include the amount you're charging. If there are multiple items or services, list each one with its own cost, then add them up to show the total amount due.

At the bottom, write how you want to be paid and where the payment should go. For example: "Please pay by check to [your name]" or "Bank transfer to [your account details]" or "Cash payment in person." Make it as straightforward as possible for the person to know exactly what to do.

Creating an invoice by hand or using a template

The simplest way to create an invoice is to write one by hand on a piece of paper. Write clearly, include all the information above, and keep a copy before you give the original to the person who owes you money. This works fine for small, one-time payments.

If you want something that looks more professional or that you can reuse, use a free template. Microsoft Word and Google Docs both have invoice templates built in. Open Word or Google Docs, search for "invoice template," pick one you like, and fill in your information. You can save it and use the same template again the next time you need an invoice.

Templates save you time because the layout is already done — you just fill in the blanks. They also make sure you don't forget any important information. After you fill in the template, save it with a name that includes the date and the person's name, like "Invoice_Smith_Jan2025.docx."

Using free invoicing software

If you create invoices regularly, free invoicing software can make the work faster. Wave and Square Invoices are two popular options that don't charge you anything. Both let you create an invoice, send it by email, and track whether the person has paid.

To use Wave, you create a free account on their website, enter your business information once, and then create new invoices by filling in the customer's name, what they owe you for, and the amount. Wave numbers your invoices automatically and stores them so you can look back at old ones. You can send the invoice by email directly from Wave, and the person can pay you through the software if they choose to.

Square Invoices works similarly. You set up a free account, create an invoice, and send it by email or text. The person can pay through a link in the invoice using a credit card or bank transfer. Both services keep a record of what you've sent and what's been paid.

These tools are most useful if you send invoices to different people regularly. If you only need one or two invoices, a template is probably faster.

Numbering and tracking your invoices

Give each invoice a number. Start with Invoice #1 and go up from there. This helps you keep track of all the invoices you've sent and makes it straightforward to refer to a specific one if there's a question. Write the invoice number at the top of the invoice, usually in the upper right corner.

Keep a record of every invoice you send. Write down the date, the person's name, the invoice number, the amount, and the due date. You can do this in a notebook, a spreadsheet, or in the invoicing software itself. This record helps you remember who owes you money and when they should have paid.

Before you send an invoice, make a copy for yourself. If you're printing it on paper, photocopy it or scan it. If you're sending it by email, save the email or the PDF. You need your own copy in case there's ever a disagreement about what was sent or when.

What to do if the person doesn't pay by the due date

If payment doesn't arrive by the due date, wait a few days and then contact the person. They may have forgotten, or the payment may be in the mail. A straightforward phone call or email saying "I wanted to check in about invoice #3 — it was due on January 15th" is usually enough.

If they say they can't pay on time, ask when they can pay and get that in writing if possible. If they say they didn't receive the invoice, send it again. If they refuse to pay or stop responding, you may need to decide whether to pursue the debt through small claims court, but that's a separate decision that depends on how much money is involved and your local laws.

For future invoices, you can add a note at the bottom stating what happens if payment is late — for example, "A late fee of $10 will be charged for payments received more than 10 days after the due date." Make sure both of you agree to this before you send the invoice.

Frequently Asked Questions

Do I need to use a specific format or template?

No. An invoice can be handwritten or typed, straightforward or detailed. What matters is that it includes your name and contact information, the other person's name, a clear description of what they owe you for, the amount, and the due date. As long as someone reading it understands what they owe and how to pay, it's a valid invoice.

What if I'm invoicing a friend or family member?

An invoice works the same way. It actually helps prevent misunderstandings between people who know each other. A straightforward, friendly invoice that says "I lent you $200 on January 10th, due back by February 10th" is clearer than relying on memory, and it shows you're serious about being repaid.

Can I charge interest or late fees on an invoice?

You can, but only if the person agrees to it before you send the invoice. Write the late fee or interest rate on the invoice itself so there's no question. For example: "If payment is not received by the due date, a late fee of $15 will be added." Make sure you both understand and accept this before they owe you the money.

What if I need to change an invoice after I've sent it?

Create a new invoice with a new number and mark it "Revised Invoice" or "Invoice #5 - Revised." Explain what changed — for example, "The amount has been corrected from $150 to $175." Send the revised invoice and ask the person to disregard the old one. Keep both copies in your records so you have a clear history of what happened.

Do I need to keep invoices forever?

Keep invoices for at least three to seven years, depending on your location and whether the person is a business or individual. This protects you if there's ever a question about payment or if you need proof of the transaction for taxes or a legal dispute. After that time, you can usually throw them away safely.