To write an invoice, put your business name and contact information at the top, add the buyer’s details, assign a unique invoice number, list each product or service with its quantity and price, state your payment terms, and show the total amount due with instructions for where to send payment. Get those pieces right and the invoice moves through the buyer’s accounting department without friction. Miss one, and payment stalls.
What an Invoice Must Contain
No single federal law dictates the format of a private-sector invoice, but accounting departments expect the same elements on every bill they process. Leave one out and the invoice is likely to be held for review instead of paid.
- Your full legal business name, mailing address, phone number, and email.
- The buyer’s legal business name and address, labeled “Bill To.”
- A unique invoice number. Number them sequentially so you never duplicate one and so both sides can reference it later.
- The invoice date (when you issued it) and, separately, the date the goods were delivered or the services performed.
- An itemized description of each product or service, with quantity, unit price, and line total.
- Payment terms, such as “Net 30” or “Due on receipt.”
- The total amount due after tax, discounts, and any adjustments.
- Remit-to information: a mailing address for checks or bank details for electronic transfers.
The “Bill To” and “Remit To” fields deserve extra attention when your business name or payment address differs from your main contact information. A mismatch between those fields is one of the most common reasons an invoice gets flagged instead of paid.
Filling It In Step by Step
Most people build invoices in a word processor, a spreadsheet, or an accounting platform like QuickBooks, FreshBooks, or Wave. The templates handle the layout and auto-calculate line totals, subtotals, taxes, and the grand total, which removes a common source of math errors.
Start at the top with your own business details, then enter the buyer’s information. Assign the next sequential invoice number and the date. In the body, create one row per item. Describe each item clearly enough that someone in the buyer’s accounting department, who may have no knowledge of the project, can match it to a purchase order. For each row, show the quantity, the agreed rate, and the extended amount.
Total the lines into a subtotal. If the sale is subject to sales tax, add the applicable rate for the jurisdiction where the sale occurs. Combined state and local sales tax rates across the United States range from zero in states without a sales tax to over 10 percent in the highest-taxed jurisdictions, so the right rate depends on both your location and what you’re selling. Apply any negotiated discount, then display the grand total prominently. Review everything once more, then save the finished file as a PDF or another non-editable format before sending.
Setting Payment Terms
Payment terms tell the buyer when the money is due. “Net 30” means payment within 30 days of the invoice date. “Net 60” means 60 days. “Due on receipt” means immediately. State the terms clearly on every invoice. The clock typically starts on the invoice date, not the delivery date.
An early payment discount can speed collection. “2/10 Net 30” means the buyer gets a 2 percent discount for paying within 10 days; otherwise the full amount is due in 30 days. On a $10,000 invoice, paying inside that window saves the buyer $200. Spell the terms out so there is no ambiguity about either the deadline or the discount amount.
If you plan to charge a late fee for overdue payment, you need written agreement to that fee before the work begins. You generally cannot bolt on a penalty after the fact if your original invoice or contract did not mention one. Allowable late fees vary by state, but a common range is 1 to 2 percent per month on the outstanding balance.
Sending the Invoice
Email is the usual delivery method. Attach the invoice as a PDF so the formatting survives and the buyer cannot edit it in transit. Larger companies often require vendors to upload invoices directly to an accounts payable portal, which confirms receipt and feeds the document into an automated approval workflow. Follow the buyer’s submission instructions exactly. Sending to the wrong address or skipping the portal can add weeks to your timeline.
Paper mail is still an option when the buyer prefers it. If proof of delivery matters because of a dispute or a tight contractual deadline, certified mail through the U.S. Postal Service gives you a tracking number and a delivery confirmation. Hold onto the receipt.
Electronic invoices and electronic signatures carry the same legal weight as paper ones. Under federal law, a signature, contract, or other record cannot be denied legal effect simply because it is in electronic form, as long as the transaction affects interstate or foreign commerce.1Office of the Law Revision Counsel. 15 USC 7001 – General Rule of Validity A digitally signed PDF is as enforceable as a hand-signed paper copy, provided both parties have agreed to conduct business electronically.
If You’re an Independent Contractor
If you provide services to a business as a non-employee, the payer will likely ask you to complete IRS Form W-9 before your first invoice. The W-9 collects your taxpayer identification number: your Social Security number for individuals, or your employer identification number if you operate through a business entity.2Internal Revenue Service. Form W-9 (Rev. March 2024) Request for Taxpayer Identification Number and Certification The payer uses that information to file a Form 1099-NEC reporting what they paid you during the year.
For payments made after December 31, 2025, the 1099-NEC reporting threshold rose from $600 to $2,000. A business that pays you $2,000 or more in a calendar year for non-employee services must report the total to the IRS.3Internal Revenue Service. Form 1099 NEC and Independent Contractors Payments below the threshold are still taxable income to you; the threshold only decides whether the payer files the form. Keeping your W-9 current avoids backup withholding, where the payer must withhold a percentage of your payment and send it to the IRS instead of to you.2Internal Revenue Service. Form W-9 (Rev. March 2024) Request for Taxpayer Identification Number and Certification
Your TIN does not belong on the invoice. The W-9 is a separate document the payer keeps on file. The invoice just needs to identify your business clearly enough for the payer to match the payment to the right W-9.
Fixing a Mistake on an Invoice You Already Sent
Never alter an invoice after sending it. If you find a wrong quantity, an incorrect price, or a duplicated charge, issue a credit memo. A credit memo is a separate document that references the original invoice number and reduces or cancels the amount owed. Include a credit memo number, the date, the original invoice number, a description of the error, and the adjusted amount.
After the credit memo, send a corrected invoice with a new invoice number for the accurate amount. The three documents, linked by their reference numbers, preserve a clean paper trail for your books and for the buyer’s audit records.
When the Buyer Doesn’t Pay
If payment does not arrive by the due date, start with a polite follow-up email or phone call. Many late payments are administrative backlogs rather than refusals. Attach the original invoice and reference the invoice number and due date. If the buyer’s system shows no record of it, resend promptly.
If a reminder does not resolve the issue, send a formal past-due notice listing the original amount, the days overdue, and any late fees or interest your contract allows. For debts that stay unpaid, your options include hiring a collection agency, filing in small claims court for smaller amounts, or filing a civil lawsuit. Every state sets a statute of limitations on how long you have to sue on an unpaid debt. For written contracts and open accounts, that window typically runs between three and ten years, depending on the state. A partial payment or a new payment agreement can restart the clock, so keep detailed records of every communication and transaction.
One narrow exception: if your buyer is a federal agency, the Prompt Payment Act requires the agency to pay interest automatically on late payments at a rate set by the Treasury Department.4Office of the Law Revision Counsel. 31 USC 3902 – Interest Penalties Private-sector buyers are not subject to that rule.
How Long to Keep the Invoice
The IRS requires you to keep records that support the income, deductions, or credits on your tax return for as long as the statute of limitations on that return stays open.5Internal Revenue Service. How Long Should I Keep Records In most cases that means at least three years from the filing date. Several situations extend the period:
- Six years, if you underreport income by more than 25 percent of the gross income shown on your return.
- Seven years, if you claim a deduction for bad debt or worthless securities.
- Indefinitely, if you do not file a return or file a fraudulent one.
Employment tax records must be kept for at least four years after the tax is due or paid, whichever is later.5Internal Revenue Service. How Long Should I Keep Records The IRS specifically lists invoices as supporting documents businesses should retain for gross receipts, purchases, expenses, and asset transactions.6Internal Revenue Service. What Kind of Records Should I Keep Keeping both the invoices you send and the ones you receive for at least seven years covers the longest common retention scenario and protects you if an audit ever reaches back that far.