A date. “Net 30” requires the reader to find your invoice date, add thirty days, and agree with your arithmetic — three chances to defer the decision. “Due 23 September 2026” is a deadline someone can put in a calendar, and it is what accounts payable systems key on.

Should I add a late payment fee?

State a policy if you intend to enforce one, and keep it identical to what your contract says — an invoice cannot introduce a term the agreement does not contain. A line in the terms field is enough. The real lever on payment speed is usually not the penalty; it is whether the invoice reached the right person with everything they needed to approve it.

What if the client wants a purchase order number on it?

Put it in the reference field, and treat it as required rather than optional. In any company large enough to have a PO process, an invoice without the PO number does not get matched, does not get approved, and comes back to you a fortnight later.

Do I need to send a quotation first?

For anything above a trivial amount, yes — and it saves the argument later. Send a quotation, and once it is accepted switch the document type to Invoice and keep the same line items. A proforma sits between the two: it looks like an invoice and states what will be charged, but it is not a demand for payment and carries no tax credit.

How should I name the file?

So that it can be found in a folder of four hundred others. The generator names it by document type, number and client — “Invoice - INV-202608-001 - Northline Retail.pdf” — which sorts sensibly and tells the recipient what it is before they open it.

What to Put on an Invoice — And What Gets It Paid Faster

The seven lines that matter

01Name both parties in full, with the address and tax number each of them files under.
02Give the invoice a unique number from a series you keep consecutive.
03Date it, and state the due date as a date rather than a number of days.
04Itemise the work so each line can be checked against something the client agreed to.
05Show the tax separately from the amount it is charged on.
06State exactly how to pay, in the same document.
07Send it as a PDF to the person who actually processes it.

The four omissions that hold an invoice up

No purchase order or reference. In any organisation with a procurement process, an invoice that cannot be matched to an approved order does not enter the payment run. It sits with someone who lacks the authority to approve it and does not know who has it. Ask for the PO number before you start the work, not after you have invoiced for it.

A due date the reader has to calculate. “Net 30” is an instruction to do arithmetic. “Due 23 September 2026” is a deadline. One of those gets entered into a system; the other gets deferred until somebody works it out.

A single line reading “services rendered”. An invoice has to be checkable by someone who was not in the room. One line for ₹2,50,000 gives them nothing to verify and every reason to escalate it. Three lines that each correspond to something the client agreed to can be approved by the person who agreed to it.

No payment instructions. Account name, account number, IFSC or SWIFT, UPI ID — on the invoice itself, not in the covering email that gets detached the moment the PDF is filed. Any question here costs you a round trip and a week.

Send it to a person, and to the process

The person who commissioned the work rarely pays for it. Send the invoice to them *and* to accounts payable, so the person who can approve it and the system that will pay it both have it on day one. If there is an invoicing portal, the portal is the only route that counts — everything else is a copy.

Keep a series, and keep the file

One consecutive number series across every invoice you raise, regardless of which tool raised it. Keep the PDF: it is the record, and unlike a draft in a browser it does not disappear when a machine is replaced.

What to put on an invoice

The seven lines that matter

The four omissions that hold an invoice up

Send it to a person, and to the process

Keep a series, and keep the file

Lay one out now

Common questions

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Quotation format

Freelance invoice format

Invoice format in India