What Should a Small Business Invoice Include?

By Bill Stilwell · Last reviewed October 17, 2026

The short answer

A good invoice shows who is billing whom, what was done, what it costs, when payment is due, and exactly how to pay. Use one template for every customer, number every invoice in order, and send the final invoice as soon as the customer confirms the job is done. Keep a copy, because the IRS lists invoices as one of the records that support your income.

What this means

10.7.5 Invoices

An invoice is a written request for payment. A standard one includes:

Your business name, exactly as you use it in public, plus your legal name if it’s different (see 8.1.1 Legal Name)
Your address, phone, and email
The customer’s name and address
A unique invoice number
The invoice date and the due date
A line for each service or product, with quantity and price
Any deposit or progress payments already paid, subtracted from the total
Sales tax, if your state requires it on what you sold (see 10.2.2 Sales Tax)
The balance due
How to pay: the payment methods you accept and where to send money (see 10.7.1 Payment Methods)
Your payment terms and any late fee your agreement allows (see 11.1.6 Payment Terms)

17.9.3 Final invoice

The final invoice closes out the job. It should match the agreement, plus any signed change orders, minus what the customer already paid. If the numbers don’t line up with what the customer expects, stop and fix it before you send it.

Made-up example: Pine Ridge Landscaping finishes a patio job. The office pulls the signed estimate, one approved change order, and the deposit record. The final invoice lists the original price, the change order, the deposit credit, and the balance. It goes out by email the same afternoon, with a pay link and the due date in the subject line.

Why it matters

Unclear invoices get paid late. A missing due date or vague payment instructions gives customers a reason to wait.
Wrong totals start arguments. A final bill that doesn’t match the agreement is one of the fastest ways to turn a happy customer into an unhappy one.
Gaps in numbering look bad in an audit. Missing or duplicate numbers make it harder to prove your income records are complete.
Your records depend on them. The IRS lists invoices among the documents that show the amounts and sources of your gross receipts.

Who this applies to

Every business that bills customers after a sale. Shops that take payment at the register still need receipts, and many still send invoices to business customers. If you get paid in full up front, you’ll still want a paid invoice or receipt for your records.

How to do it

Pick one tool. Use your bookkeeping software or one invoicing tool so every invoice is numbered and stored in one place (see 10.5.5 Invoice Records).
Build one template with every field listed above. Use your public business name and logo so customers recognize you.
Set a numbering system that never repeats, for example 2026-0001. Never reuse a number, even for a canceled invoice. Mark it void instead.
Write your standard terms, like “Due within 15 days of the invoice date.” Make sure they match your agreement.
Add clear payment instructions. If you accept bank transfers, explain how customers can confirm your account details by phone before they pay (see 10.6.3 Vendor Approval and Bank-Change Verification).
Before each final invoice, check it against the paperwork: agreement, change orders, deposits, and progress payments.
Send it the same day or the next business day after the customer signs off (see 10.7.4 Final Payment).
Track it on your accounts receivable list until it’s paid (see 10.5.6 Accounts Receivable).
Follow up on a set schedule if it goes past due (see 16.6.5 Late Payments and Collections).

What proof to keep

A copy of every invoice, including voided ones
The paperwork each final invoice was checked against
The payment record that matches each invoice
Your invoice template and written terms

Keep them in your bookkeeping system or your financial records folder. Ask your tax professional how long to keep them (see 9.8.2 Record Retention Periods).

Common mistakes

No due date. “Upon receipt” means different things to different people. Use a date.
Forgetting the deposit credit. The customer catches it, and trust drops.
A different name on the invoice than on the sign and the GBP. Customers think it’s a scam or a mistake.
Editing a sent invoice. Issue a corrected invoice or a credit note instead, so your records stay clean.
Putting full bank details in a plain email with no way to verify them. Fake invoices with changed bank details are a common fraud.
Sending the final invoice weeks later. It gets paid later too.

When to get help from a pro

A CPA or bookkeeper can help set up your invoice template and numbering so it matches your books. Questions to ask:

What has to be on my invoices for sales tax in my state?
How should I record deposits and credits so they match the invoice?
How long should I keep invoices and related records?

Bill’s note

[Bill: add a short note. For example, what you put on SiteSmarty invoices to cut down on “what is this charge?” emails, or a time a late or confusing invoice delayed payment.]

How I did this for SiteSmarty

[Date I did this:]
[What I actually did, step by step: the invoicing tool, template, and numbering I set up]
[What it cost and how long it took:]
[What surprised me or what I’d do differently:]
[Screenshot or photo to add, with private info blurred: a sample SiteSmarty invoice]
[Result so far:]

Questions people ask

What has to be on an invoice? Your business name and contact details, the customer’s name, an invoice number, the date, what you did, the price, any taxes, the balance due, the due date, and how to pay.

When should I send the final invoice? As soon as the customer confirms the job is complete, ideally the same day.

Can I change an invoice after I send it? It’s cleaner to void it and issue a corrected one, or issue a credit note, so your records show what happened.

How long should I keep invoices? It depends on tax rules and your state. Ask your tax professional, and see 9.8.2 Record Retention Periods.

Audit check

Line	Question	Pass looks like	Fail looks like	Evidence to collect
10.7.5 Invoices	Does every invoice use one template with a unique number, due date, and payment instructions?	One template. Numbers in order with no gaps or repeats. Due date and pay instructions on every invoice.	Handwritten or mixed formats. Missing due dates. Reused numbers.	Invoice template and the last 10 invoices in number order
17.9.3 Final invoice	Does each final invoice match the agreement, change orders, and payments received?	Final invoice total ties to the paperwork and is sent within 1 business day of sign-off.	Totals that don’t match. Deposits not credited. Invoices sent weeks late.	5 closed jobs with agreement, change orders, deposits, and final invoice side by side

Where this fits

Do this first: 10.7.4 Final Payment

Do this next: 10.7.6 Payment Security

Sources

IRS, "What kind of records should I keep" (checked October 17, 2026)
Google Business Profile Help, "Tips to improve your local ranking on Google" (checked October 17, 2026)

This page explains general rules and Bill's own experience. It is not legal, tax, or insurance advice. Talk to a qualified professional about your situation.