What Information Should an Invoice Include?

An unpaid invoice is uncomfortable, but following up does not need to be aggressive. In many cases, payment is late because the invoice was overlooked, sent to the wrong person, waiting for approval, or scheduled for the next payment run.

A calm, organized follow-up process gives the client a chance to fix the issue while protecting your cash flow.

Check the invoice before contacting the client

Before sending a reminder, confirm that the invoice is actually overdue and that your own information is correct. Check that it was sent successfully, went to the correct billing contact, contains the right due date and PO number, and uses accurate payment details.

If the invoice itself is missing information, fix the problem before chasing payment.

First reminder: friendly and simple

A first reminder can be sent shortly after the due date. Keep the tone neutral. Assume the delay may be accidental.

Subject: Payment reminder — Invoice INV-1051

Hello Maya,

I’m following up on Invoice INV-1051 for £1,200, which was due on 12 September. I’ve attached another copy for convenience.

Please let me know if you need any additional information from me to process the payment.

Thank you,
Alex

Second reminder: be more specific

If there is no response after the first reminder, send a second message. Repeat the invoice number, amount, and due date. Ask for an expected payment date.

“Could you please confirm when payment is scheduled?” encourages a concrete answer instead of another vague delay.

Contact the right person

The person who hired you may not process invoices. Ask whether there is an accounts-payable contact, finance department, or supplier portal.

For larger clients, an invoice may be stuck because the PO number is missing, the manager has not approved the work, the supplier account is incomplete, or the invoice missed a payment-run cut-off.

Keep reminders factual

A payment reminder should focus on the transaction. Avoid emotional language. Useful facts include invoice number, invoice date, amount due, original due date, days overdue, payment instructions, and previous correspondence.

Clear facts make the message easier for the recipient to forward internally.

Attach the invoice again

Even if the client already has it, attaching the invoice again removes one excuse for delay. Make it easy for the person reading your message to forward everything to finance.

If you need a clean replacement copy, use the Invoice Generator.

What if the client disputes the invoice?

A disputed invoice is different from an ignored invoice. Ask the client to explain the specific issue. It may relate to scope, quantity, price, quality, tax, PO number, or billing details.

Review the original quotation, contract, emails, and delivery records. If a correction is genuinely required, issue the appropriate corrected document according to your accounting process.

What if the client cannot pay yet?

Decide how you want to respond based on the amount, relationship, and risk. Some businesses agree a payment plan. Others require full payment according to the original terms.

If you agree a new schedule, confirm it in writing with exact dates and amounts.

Use clear payment terms from the beginning

Many payment problems can be reduced before the project starts. State the payment schedule in the quotation or agreement. Consider deposits for new clients or larger projects.

Our Quotation Generator lets you include terms before the customer accepts the work.

Do not wait too long to follow up

Ignoring an overdue invoice for weeks can make collection harder. A consistent reminder schedule is better than occasional messages sent only when cash flow becomes urgent.

For example, you might send a friendly reminder a few days overdue, a second reminder around a week later, and then make a phone call or use a more formal process if the delay continues. Choose a process appropriate for your business and local law.

Keep records of communication

Save the invoice, emails, payment promises, and any corrections. Good records help you understand the history if the issue continues.

Should you charge late fees?

Late fees depend on your contract and applicable law. Do not add a surprise fee that was never agreed or is not legally permitted. If you intend to use late charges, state the terms clearly in advance.

Prevent future late payments

After the invoice is resolved, consider whether your process needs improvement. Useful changes can include deposits, shorter terms, milestone billing, confirming the billing contact, adding PO numbers correctly, sending invoices immediately, and using consistent numbering.

For the document itself, our guide to what information an invoice should include can help you avoid missing details.

Create a clear invoice that is easy to process

Add the correct client details, due date, references, line items, taxes, totals, and payment terms.

Open Invoice Generator

Frequently asked questions

How soon should I follow up?

Many businesses send a friendly reminder within a few days of the due date. The exact timing depends on the client relationship and payment process.

What should I say?

State the invoice number, amount, due date, and that payment appears outstanding. Attach the invoice and ask whether any information is needed.

Should I call the customer?

A phone call can be useful after email reminders, especially if you need to identify the right finance contact.

Final thoughts

Following up on an unpaid invoice is a normal business task. Start politely, use accurate facts, make the invoice easy to access, ask for a payment date, and keep records. A calm system is more effective than waiting until the situation becomes urgent and then sending an emotional message.