By Safock Procurement Research Team7 min read
An invoice can be paid late without anyone disputing it, simply because it is missing something the customer's accounts team needs before they can pay: a due date they can schedule, an address for the right company, or bank details. Each gap means an email, a wait for the reply, and a corrected invoice.
This is the short list of what goes on an invoice, and what each item does to get you paid.
Requirements differ between countries, and tax invoices (for VAT or sales tax) can need more. The UK government's guidance is a clear baseline. It says an invoice must include:
(GOV.UK, Invoices: what they must include). Limited companies there must also use their full registered name, and sole traders trading under a business name must give an address where legal documents can be delivered.
That list covers what makes an invoice valid. Two more items decide when it gets paid: the payment terms and due date, and how to pay you.
| Item | What it does |
|---|---|
| Unique invoice number | Lets the customer, and you, refer to this invoice and no other. Reusing a number is how invoices get paid twice or not at all |
| Your name, address and contact details | Tells the customer who to pay and who to ask if something is unclear |
| Customer's name and address | Gets the invoice booked to the right company. A business may trade under one name and be registered under another |
| Description of each charge | Lets the person approving it recognise what they're paying for without asking you |
| Supply date | Shows when the work was done or the goods delivered, which matters for tax and for the customer's records |
| Invoice date and payment terms | Together they set the due date |
| Amounts, tax and total | What is owed, and how it was worked out |
| How to pay you | Bank details, a payment link or a cheque address. Without it, nobody can pay, however willing |
| Your tax ID | Required on tax invoices in many places, and business customers often need it for their records |
Any scheme works if no two invoices can ever share a number. A plain sequence (INV-1042, INV-1043) is simplest. Adding the year (INV-2026-042) or a customer code is fine. Don't restart the sequence each year without the year in the number, and never reuse a number after a mistake: issue a credit note against the wrong invoice and a new invoice with the next number.
Payment terms such as Net 15 mean payment is due 15 days after the invoice date. Due on receipt means immediately. Print the resulting date on the invoice as well. An accounts team schedules payments by date, and "Net 15" makes them work it out.
Write terms that can only be read one way. "Payment appreciated promptly" isn't a term. The Bollard invoice generator, faced with terms it can't read, assumes 30 days, and a customer may assume the same, or longer.
The general invoice generator's built-in example is a caterer invoicing an advisory firm for a board lunch, on Net 15 terms.
| Description | Qty | Unit | Price | Amount | Taxable |
|---|---|---|---|---|---|
| Board lunch catering, 24 guests | 24 | EA | $38.50 | $924.00 | Yes |
| Coffee and pastry service | 1 | EA | $180.00 | $180.00 | Yes |
| Event staff (2 people × 4 hours) | 8 | HR | $45.00 | $360.00 | No |
The subtotal is $1,464.00. Sales tax at 8.75% applies to the two taxable lines, $1,104.00, adding $96.60. The total is $1,560.60. Dated October 19, 2026 on Net 15 terms, it is due November 3, 2026.
Three details make it easy to pay. The staff hours are a separate, untaxed line, so the tax is visibly right. The invoice gives a service date, so the customer can match it to the event. And the payment details are printed on the invoice itself.
Tick what your current invoice includes, and choose your terms and invoice date. The checks and verdict are the invoice generator's. "How to pay you" starts unticked, because it is the item most often left off.
Tick what your invoice includes
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Missing essentials
Due Tuesday, November 3, 2026. Print that date on the invoice next to “Net 15”.
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Invoice Generator
Add your logo, customer and line items, mark which lines are taxable, set your terms, and download a clean PDF with the due date and payment details printed on it. No sign-up, and the invoice is made in your browser.
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Larger customers often issue a purchase order and match every invoice against it before paying. Then the PO number, the legal entity on the PO, and prices and quantities that match the PO and the delivery all become essential. Our guide to invoicing against a purchase order covers that checklist, and the PO invoice generator checks an invoice against the PO before you send it.
At minimum: a unique invoice number, your business name, address and contact details, the customer’s name and address, a description of what you are charging for, the date it was supplied, the invoice date, the amounts and any tax, the total owed, the payment terms or due date, and how to pay you. Some countries add more, such as VAT details.
Give every invoice a unique number and never reuse one. A simple sequence such as INV-1042, INV-1043 works. Adding the year, or a customer code, is fine as long as no two invoices can end up with the same number.
Payment is due 15 days after the invoice date. Print the actual due date on the invoice as well, because a customer’s accounts team schedules payments by date, not by terms.
It depends on where you are and whether you charge sales tax or VAT. Many countries require it on tax invoices, and business customers often need it for their own records, so it is a good habit to include it.
Quote the PO number exactly, bill the legal entity and address on the PO, and keep prices and quantities to what the PO and the delivery support. Larger customers often hold invoices that don’t match their PO.