What invoice means
An invoice is a demand for payment with the details attached.
It names who is charging, who is being charged, what was supplied, how much is owed, and when it is due. In a dispute it is the primary evidence that work was done and a sum became payable.
People confuse invoices with receipts constantly. An invoice asks for money. A receipt confirms money was received. They sit on opposite sides of the payment.
How it is used
For freelancers and small businesses, the invoice is the whole engine of getting paid. It should reference the agreement or purchase order it relates to, describe the work in terms the client's finance team can match against what they approved, and state payment terms clearly.
Vague invoices delay payment more than any other single factor. Where a client's process requires a purchase order number and your invoice does not carry one, it will sit in a queue nobody is chasing.
Key features
- Unique invoice number, for both parties' records
- Names and addresses of supplier and customer
- Description of goods or services, dates, quantities and rates
- Total due, with VAT shown separately where it applies
- Payment terms, due date and bank details
- Reference to the purchase order or contract where one exists
How this works in Nigeria
Two tax points matter. VAT should be shown separately where the supplier is required to charge it, because a client cannot process it correctly from a lump figure.
Withholding tax is the other, and it catches freelancers out constantly. Corporate clients frequently deduct withholding tax at source and remit it to the tax authority, then pay the balance. That deduction is not the client shortchanging you, and the credit note they issue is what you use against your own tax. Invoices should be raised gross so the arithmetic is clear.
Invoice vs receipt vs purchase order
A purchase order comes first, issued by the buyer to say what they are ordering and on what terms. It is the buyer committing.
The invoice comes after delivery, issued by the supplier to request payment for what was supplied.
The receipt comes last, confirming the money was actually received. In a well run transaction you see all three, and in a dispute the sequence is what proves what was agreed, what was delivered and what was paid.
Limits and risks
An invoice is not a contract. It records a claim for payment, but if there was no agreement to supply on those terms, issuing an invoice does not create one.
It also does not by itself compel payment. Where a client ignores it, the next steps are a reminder, then a formal demand letter, then whatever dispute process the contract provides for.
Worth knowing
Ask for the client's purchase order number and payment process before you deliver. Most late payment in Nigeria is not refusal, it is an invoice sitting in a system it was never correctly entered into.