How to Invoice a Company for Freelance Work

Short answer: Knowing how to invoice a company for freelance work means satisfying an accounts payable process, not just sending a bill. Before you invoice, get the AP contact, the payment terms, whether a purchase order number is required, and submit a W-9. Then send a PDF carrying a unique invoice number, your legal name and address, the client’s legal entity name, the PO number if there is one, itemised work with dates, the total, the due date, and how to pay. An invoice missing the PO number is the most common reason payment stalls.

Invoicing an individual is a conversation. Invoicing a company is a process run by people who have never met you and will not chase you for missing information — they will simply not pay. If you are starting from scratch, how to invoice as a freelancer covers the basics; this page is about the business-client version specifically.

What makes invoicing a company different?

A person pays you because they remember agreeing to. A company pays you because your invoice cleared a checklist.

	Invoicing a person	Invoicing a company
Who decides	Your client	Accounts payable, not your client
Timing	Usually quick	Net 30 or longer, on a payment run
Paperwork first	None	W-9, vendor onboarding, sometimes a PO
Reference required	No	Often a PO or project code
If a detail is missing	They ask you	It sits in a queue
Who you chase	The client	AP, with your client cc’d

The practical consequence: most of the work happens before you invoice. Ten minutes of setup at the start of an engagement removes most of the reasons an invoice goes unpaid.

What should I ask before I send the first invoice?

Ask your contact these five questions as soon as the work is agreed. They are routine, and asking them reads as professional rather than pushy.

1. Who should the invoice go to, and to what address? Usually a shared inbox such as ap@ or invoices@, not your day-to-day contact. Send it there and cc your contact.
2. What are the payment terms? Net 15, Net 30, Net 45, Net 60. This determines your due date, and it is negotiable at the start of an engagement in a way it never is afterwards.
3. Is a purchase order required? If yes, you need the PO number before you invoice. Many AP systems reject an invoice with no matching PO automatically, without a human ever reading it.
4. What is the exact legal entity name to bill? “Acme” on the website may be “Acme Holdings LLC” in the accounting system. Bill the wrong entity and it bounces.
5. Is there a vendor portal or a supplier form? Larger companies require you to register before your first invoice is payable.

What paperwork does the company need from me?

In the United States, a Form W-9. The client needs your legal name, business name if different, tax classification, address, and TIN — your SSN or your EIN — so they can issue you a 1099-NEC in January if they paid you $600 or more. Fill it once per client and keep a copy.

An EIN is free from the IRS and lets you put a number other than your Social Security number on a form you email to strangers. You do not need an LLC to get one — see do I need an LLC to freelance.

You may also be asked for:

• Bank details or an ACH form, for direct deposit.
• A certificate of insurance, for on-site or higher-risk work.
• A signed vendor agreement or MSA, before any PO is issued.
• A W-8BEN instead of a W-9, if you are a non-US freelancer billing a US company.

What has to be on an invoice to a company?

Everything on a standard invoice, plus the references AP matches against. The generic field list is in what to include on an invoice; these are the business-client additions.

The essentials:

• A unique invoice number, sequential and never reused.
• Issue date and due date — write the actual date, not “Net 30.” AP should not have to calculate.
• Your legal name or business name, address, and contact email.
• Your EIN or tax reference, if you use one.
• The client’s full legal entity name and billing address.

The business-client additions:

• PO number, if one exists — near the top, clearly labelled.
• The project, cost centre or department code your contact gave you.
• Your contact’s name, so AP knows who approves it.
• Itemised lines with a short description, the dates or period covered, quantity or hours, rate, and line total.
• Subtotal, any tax, and the total due in the currency you agreed.
• Payment instructions — bank details for ACH or transfer, or a payment link.

Format matters. Send a PDF, never a word processor file or a spreadsheet, and name the file so a stranger can identify it: Invoice-2026-014-YourName-Acme.pdf. Some AP systems scan filenames.

When should I send it, and to whom?

• Send it the day the work or the billing period ends. Payment terms start when the invoice is received, so a week’s delay in sending is a week’s delay in being paid.
• Send it to the AP address, cc your contact. Your contact approves; AP pays. Skipping either one costs you a cycle.
• Watch the payment run. Many companies pay on fixed dates — the 1st and 15th, or once monthly. An invoice that arrives one day after the cut-off waits for the next run regardless of its due date. Ask when the run is and send before it.
• One invoice per PO. Do not combine two POs on one invoice or split one PO across invoices unless the client asked for milestone billing.

What do I do when a company does not pay?

Assume an administrative cause before a bad-faith one. Most late payment to freelancers is a stalled queue, not a refusal.

Day after due date — confirm receipt. A short email to AP, cc your contact: reference the invoice number, confirm it was received and entered, and ask for the expected payment date. Do not apologise and do not re-negotiate.

Day 7 — ask your contact to check approval. Invoices most often stall waiting for the approver, and your contact usually is the approver. One line: “Invoice 2026-014 is still showing unpaid — could you confirm it has been approved on your side?”

Day 14 — escalate in writing. Restate the invoice number, amount, due date, and days overdue. Reference the agreed terms. Ask for a payment date, not an apology.

Day 30 — state consequences. Pause new work, apply the late fee if your terms include one, and put both in writing. The tactics are covered in how to get clients to pay.

Prevent the whole sequence by invoicing a deposit for new business clients, keeping terms at Net 15 or Net 30 where you can, and never letting unbilled work accumulate for months.

Do I need to keep a copy of what I sent?

Yes, and it needs to be the invoice as sent, not a reconstruction. If a client disputes an amount two years later, or your return is examined, the record that settles it is the original PDF with its number, date and line items.

That is also why invoice numbers must be sequential and unique: a numbered series is self-auditing. A gap is a question you will have to answer.

Keel: Invoice Maker & Receipts creates business-ready PDF invoices on your iPhone with custom numbering, your logo and brand colour, and a payment link you can drop on as a QR code — and it keeps every invoice you have sent, on device. There is no account, no bank connection, and no cloud sync; the App Store privacy label reads “Data Not Collected.” When your accountant needs the year, you export it as one file.

Keel is free with unlimited invoices, receipts and mileage; Keel Pro is a one-time $249.99 Lifetime purchase, not a subscription. Keel on the App Store.

Frequently asked questions

How do I invoice a company for freelance work? Before invoicing, get the AP email address, the payment terms, the exact legal entity name, and the PO number if one is required, and submit a W-9. Then send a PDF carrying a unique invoice number, both parties’ details, the PO number, itemised work with dates, the total, the due date, and payment instructions.

How do I invoice a client for freelance work if there is no purchase order? Ask explicitly whether a PO is required — many companies do not use them for small engagements. If none is required, reference your contact’s name and the project or department instead, so accounts payable can route the invoice to the right approver.

Do I need an EIN to invoice a company? No. A sole proprietor can use a Social Security number on the W-9. An EIN is free from the IRS and is worth getting simply so you are not emailing your SSN to every new client. It does not require forming an LLC.

What does Net 30 mean on a freelance invoice? Payment is due 30 days after the invoice date. Terms start when the invoice is received, so send it the day the work ends. Write the actual calendar due date on the invoice as well — accounts payable should not have to calculate it.

Should I send an invoice as a PDF or a document? Always a PDF. It preserves layout, cannot be edited accidentally, and is what accounts payable systems expect. Name the file with your invoice number, your name and the client’s name, since some systems index on the filename. If the client uses a supplier portal, upload it there instead of emailing a second copy — the same invoice arriving twice can trip duplicate detection and hold payment for a cycle.

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This article is general information, not legal or tax advice.