Every invoice template has a notes line, and most sole traders leave it blank or write thank you. Used properly the invoice note is where the invoice tells the client how to pay and what happens if they do not: the account details, the purchase order or contract reference the client's accounts desk will look for, the payment terms in one sentence, the late charge if you apply one, and the job reference that ties this bill to the work. This page gives the wording for the notes line, the short invoice letter that accompanies a first invoice, and the note to send when an invoice is unpaid.
What the invoice note should carry
Payment instructions in full: bank name, account name, account and routing or sort code, or the online payment link, with the invoice number as the reference to quote. The client's purchase order or contract number where they issued one, because an invoice without it stalls in their approval queue. The terms in a sentence: payment due within fourteen days of the invoice date. The late charge if your terms include one, stated plainly. The job or project reference. A line of thanks costs nothing. What to leave out: apologies, negotiation, anything that changes the amount. The freelance invoice template on this site carries the notes line and saves your standard wording in the paid product so it is never retyped.
The invoice letter that goes with it
A first invoice to a new client, or an invoice to a client's accounts desk rather than the person you worked with, benefits from a short covering note in the email: what the invoice is for, the amount and due date, the PO reference, and who to contact with a query. Three sentences. It is not a place to re-explain the work; the invoice's line items do that. Attach the invoice as a PDF with the invoice number in the file name, put the number and amount in the subject line, and send it to the address the client's accounts desk gave you, copying the person who commissioned the work. That invoice letter is what gets the PDF opened and posted the same day.
The unpaid invoice note
When the due date passes, the note changes tone by one step, not five. On the day after the due date: a copy of the invoice with a one-line note that it fell due yesterday and asking whether there is a query. A week later: the same, with the late charge if your terms include one now shown and the statement of account attached so the client sees every open invoice at once. A fortnight later: a call, then a note confirming what was agreed on the call. Keep each note factual and keep copies, because if the invoice ends in a claim the record of reminders is what wins it. The paid product keeps the invoice, the reminders and the client together.
Questions people ask about invoice note
Should the invoice note include my bank details?
Yes, in full, with the invoice number as the payment reference. Missing bank details are the commonest reason a small invoice is paid late.
Can I put a late fee in the notes line?
Only if it was in the terms the client agreed before the work. State it plainly and apply it consistently; a surprise fee is disputed, an agreed one is paid.
How many reminders before a formal demand?
Three written reminders and a call over a month is a reasonable record. After that, a formal letter before action or a small-claims filing, with the reminders attached.