Is an invoice the same as a receipt?

No. GOV.UK says an invoice is not the same as a receipt, which is an acknowledgement of payment. The invoice lists what was supplied, gives the cost and asks for payment. A receipt records that payment has been made, so an invoice on its own is not proof that anything has been paid.

What is the difference between an invoice and a bill?

In UK usage there is none: they are two names for one document. GOV.UK writes "invoice (bill)", and Wikipedia lists invoice, bill, tab and bill of costs as names for the same commercial document. Cambridge's Business English sense describes it as a document that lists things provided or work done, gives their cost, and asks for payment.

Who issues an invoice, the supplier or the customer?

Usually the supplier. GOV.UK addresses the seller: a business that sells a customer a product or a service needs to give them an invoice by law if both are registered for VAT. The exception is self-billing, where the customer prepares the supplier's VAT invoice, with both businesses VAT registered and a written agreement in place first.

Does an invoice have to include a PO number?

Not by law. GOV.UK's list for every invoice and HMRC's list for VAT invoices do not mention a purchase order number. Some large buyers ask for one in their own terms: NHS Supply Chain (2025) its PO number, and Wickes (2022) and Travis Perkins (2021) the PO number or a four-digit cost centre number, with one PO number per invoice.

Why might a retailer query an invoice?

Because its details do not match what was received. Wickes (2022) and Travis Perkins (2021), in the same wording, look for an exact match with the products or services received, in terms of quantity, quality, price and fulfilment, and raise a Discrepancy Advice if there are inconsistencies. Transalis's EDI invoice guide explains how invoices are matched.

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What is an invoice? What a UK retailer expects on a supplier invoice

A guide to the UK invoice: the details GOV.UK lists for every invoice, the extra fields HMRC sets for a VAT invoice, what large buyers add in their supplier manuals, and how an invoice differs from a PO or a receipt.

Transalis13 November 2026

In plain terms, the invoice meaning is the supplier's written claim for what it supplied. When the customer is a retail chain, two lists decide what goes on it. The law sets one. The buyer's supplier manual can add a second, so the invoice can be matched to the order and the goods that arrived.

Key takeaways

An invoice is a document that lists the goods or services a supplier provided, gives their cost and asks for payment, and in UK usage invoice and bill name the same document.
GOV.UK lists what every UK invoice shows, from a unique number and both parties' names and addresses to the supply date, the amounts and the total owed.
A full VAT invoice adds the supplier's VAT number, a sequential number, the time of supply, each line's quantity, unit price and VAT rate, and the total VAT in sterling.
Some large buyers add their own references: NHS Supply Chain (2025), Wickes (2022) and Travis Perkins (2021) each allow only one purchase order number per invoice, and Wickes and Travis Perkins also ask for the delivery note number.
GLNs and GTINs on an invoice come from GS1's EANCOM standard for EDI invoices, not from the buyer manuals that list invoice contents.

Short answer

An invoice is a document that lists the goods or services a supplier has provided, gives their cost and asks for payment. In the UK, GOV.UK sets out what every invoice shows, and a VAT invoice adds more. A large buyer's supplier terms can add its own references on top, such as its purchase order and delivery note numbers.

What is an invoice?

The Cambridge Business English Dictionary defines an invoice as "a document that lists things provided or work done, gives their cost, and asks for payment". GS1's EANCOM standard for invoice messages describes the same document from the supplier's side: "A message claiming payment for goods or services supplied under conditions agreed between the seller and the buyer."

An invoice also points back to the order. In GS1's words: "An invoice may refer to goods, items or services related to one or more orders, delivery instructions, call-offs, etc".

Invoice and bill name the same thing. GOV.UK writes "invoice (bill)", and Wikipedia opens with "An invoice, bill, tab, or bill of costs" as names for one commercial document.

An invoice is not proof of payment. GOV.UK: "An invoice is not the same as a receipt, which is an acknowledgement of payment."

The supplier normally issues it. GOV.UK's guidance speaks to the seller: "If you sell a customer a product or a service, you need to give them an invoice (bill) by law if both you and the customer are registered for VAT (a business to business transaction)." The exception is self-billing, where, as the self-billing guide explains, "your customer prepares your VAT invoice for what you supplied".

What is an invoice for?

It is the record of the sale, held by both sides. In VAT Notice 700/21, HMRC says why it matters to each. To the supplier: "The VAT invoices you issue form a very important part of your business records and you must keep a copy of every VAT invoice you issue." To the customer: "VAT invoices are crucial to your business customers because the VAT invoice is the primary evidence that'll allow them to recover the VAT you've charged."

In a supply chain, the invoice also follows the order and the delivery. The purchase order says what the customer wants. The delivery note travels with the goods. The invoice states what was supplied and at what price. The ASN guide compares the advance shipping notice, the delivery note and the invoice. Wickes (2022) and Travis Perkins (2021) put an invoice on hold if the details "aren't an exact match with the products or services that we received from you".

What goes on a UK invoice?

GOV.UK's page Invoices: what they must include gives the list for every invoice:

"a unique identification number"
"your company name, address and contact information"
"the company name and address of the customer you're invoicing"
"a clear description of what you're charging for"
"the date the goods or service were provided (supply date)" and "the date of the invoice"
"the amount(s) being charged"
"VAT amount if applicable"
"the total amount owed"

A sole trader adds "your name and any business name being used", and "an address where any legal documents can be delivered to you if you are using a business name". For a limited company, GOV.UK says "you must include the full company name as it appears on the certificate of incorporation."

What a full VAT invoice adds

GOV.UK goes on: "You must use VAT invoices if you and your customer are VAT registered." HMRC adds that "Most commercial invoices will already meet the requirements."

Set against the general list, the VAT invoice details in VAT Notice 700/21 add:

the supplier's VAT registration number
a sequential number from one or more series, where the general list asks only for a unique one (the invoice number guide covers the numbering rules)
the time of supply, also called the tax point, and the date of issue where the two differ
on each line, the quantity, the unit price, the VAT rate and the amount excluding VAT
the total VAT, in sterling
the rate of any cash discount offered

What does a retailer expect on a supplier invoice?

Some large buyers ask for more than the law does. Neither GOV.UK's list nor HMRC's VAT list mentions a purchase order number, a delivery note number or a product code. The purchase order guide says: "GOV.UK's general list of invoice contents does not mention a PO number, so the rule comes from your customer."

The table holds only what the manuals quoted here ask for, and each binds that buyer's own suppliers on its date. Wickes, a home-improvement retailer, and Travis Perkins, a builders' merchant group, use the same wording, so they count as one text. NHS Supply Chain is a public-sector buyer, not a retailer.

What the buyer asks for	Who asks, and when	In the buyer's words
The buyer's purchase order (PO) number, and only one per invoice	NHS Supply Chain (2025). Wickes (2022) and Travis Perkins (2021), in the same text, ask for the PO number or a four-digit cost centre number, and one PO number per invoice. See the purchase order guide	"only a single purchase order number per invoice is allowed" (NHS Supply Chain)
The delivery note number	Wickes (2022) and Travis Perkins (2021), in the same text. See the ASN guide	"Delivery Note number"
The name and address of the delivery location	Wickes (2022) and Travis Perkins (2021), in the same text	"Name and address of the delivery location"
Quantity and agreed unit price	Wickes (2022) and Travis Perkins (2021), in the same text	"Quantity and agreed unit price"
The same unit and product code as the order	NHS Supply Chain (2025), a public-sector buyer	"Invoices should be stated in the same unit of issue in which our purchase order was placed." And: "Invoices should quote the same manufacturer's product code provided on our purchase order."
One invoice for each delivery	Travis Perkins (2021)	"Please send us one invoice for each delivery."
In an EDI invoice only: the buyer and supplier identified, by GLN in GS1's worked example, and a GTIN on each product line	GS1's EANCOM invoice standard, not a buyer manual. See the GLN and GTIN guides	"Identification of the buyer and supplier of goods and services is mandatory in the Invoice."

Each reference lets the buyer find its own records of the order and the delivery, and check the invoice against both. Travis Perkins checks an invoice against "the type and quantity of products that you've delivered to us". The EDI invoice guide says it in one line: "The order and delivery note references inside the invoice are what let the retailer find both records." That guide also shows how each field travels in an EDI invoice, line by line.

Where do GLNs and GTINs come in?

In the EDI invoice. None of the buyer manuals quoted above asks for a GLN or a GTIN on the invoice. GS1's EANCOM invoice standard asks for the buyer and supplier to be identified, and its worked example identifies them by GLN. Beyond buyer and supplier, it says: "The consignee or delivery party needs to be specified if different to the buyer's address." On each product line, the standard makes the GTIN mandatory where one is available.

A GLN identifies a place and a GTIN identifies a trade item. GS1 "defines trade items as products or services that are priced, ordered or invoiced at any point in the supply chain." The GLN guide and the GTIN guide cover each in full.

Invoice vs purchase order, delivery note, credit note and receipt

Document	Who sends it	When	What it does	Read more
Quote	Supplier	Before the order	States "the price that a person or company says they will charge to do a piece of work" (Cambridge)	None
Purchase order	Customer	Before supply	The customer's instruction to supply: which products, how many, where to deliver and when, under its own PO number	Purchase order guide
Delivery note	Supplier	With the goods	Confirms what is actually loaded on the vehicle at the point of delivery	ASN guide
Invoice	Supplier	After supply	Lists what was supplied, gives the cost and asks for payment under the agreed terms	This guide
Credit note	Supplier	After an invoice	Lowers the amount, for an overcharge or an agreed reduction, and points back to the original invoice	Debit note guide
Receipt	The business that received the payment	After payment	An acknowledgement of payment (GOV.UK)	None
Remittance advice	Buyer or seller	Before a payment is made	A notice of the payment to be made, covering one or more transactions	EDI transactions guide
Statement	Supplier	Each period, such as monthly	A periodic summary of the account: invoices, credit notes and payments. Not an invoice	None

The debit note guide compares credit notes, debit notes and invoices, and the EDI transactions guide covers remittance advice. Travis Perkins asks its suppliers for "a monthly statement of account".

A pro forma invoice is something else again. Wikipedia: "It is not an actual invoice". The sales order guide notes that HMRC wants pro formas "clearly marked".

How are invoices sent to retailers?

The buyer manuals named here each give a channel. Wickes (2022) gives an email address for invoices and Travis Perkins (2021) a postal address, and both take EDI invoices in their own format. M&S (2019) asks its food suppliers to invoice by EDI, and so does Ocado (2024). NHS Supply Chain (2025) asks for its specified EDI format. Suppliers without EDI systems can register invoices on its supplier portal.

The web EDI guide explains the two EDI routes: "With web EDI a person reads each order and keys each invoice, while integrated EDI connects an ERP, accounting or warehouse system so documents flow without rekeying." An eInvoice goes further, according to the what is eInvoicing guide: "An eInvoice is structured data that moves from the supplier's system to the buyer's system without retyping, and an emailed PDF does not qualify." The same guide notes: "The UK government has announced eInvoicing for VAT invoices from 1 April 2029 and named Peppol as the core network, but the legislation is not in place yet."

How Transalis fits

Where a retailer asks for invoices by EDI, the EDI page says: "Transalis now offers EDI in three categories." They are Web EDI, Integrated EDI and Enterprise EDI. The page describes Web EDI as "A secure portal where your team sees new orders the moment they land, acknowledges them in a click, and returns invoices and despatch notes, with no software to install."

For eInvoices, the eInvoicing page says: "Transalis delivers eInvoicing as a fully managed outcome, we convert the format, route it over the Peppol network, and keep it compliant, so valid invoices flow system-to-system, and stay compliant as the rules change." Transalis also sends order responses and receiving advice messages for its customers.

Book a 30-minute call with a Retail Supply Chain specialist, who will walk you through EDI and eInvoicing and how Transalis makes it simple.

Frequently asked questions

Is an invoice the same as a receipt?: No. GOV.UK says an invoice is not the same as a receipt, which is an acknowledgement of payment. The invoice lists what was supplied, gives the cost and asks for payment. A receipt records that payment has been made, so an invoice on its own is not proof that anything has been paid.
What is the difference between an invoice and a bill?: In UK usage there is none: they are two names for one document. GOV.UK writes "invoice (bill)", and Wikipedia lists invoice, bill, tab and bill of costs as names for the same commercial document. Cambridge's Business English sense describes it as a document that lists things provided or work done, gives their cost, and asks for payment.
Who issues an invoice, the supplier or the customer?: Usually the supplier. GOV.UK addresses the seller: a business that sells a customer a product or a service needs to give them an invoice by law if both are registered for VAT. The exception is self-billing, where the customer prepares the supplier's VAT invoice, with both businesses VAT registered and a written agreement in place first.
What is a supplier invoice?: It is the invoice a supplier sends to a business customer, such as a retailer, for goods or services supplied. GS1's invoice standard describes it as a message claiming payment for goods or services supplied under conditions agreed between the seller and the buyer. Wickes (2022) and Travis Perkins (2021) title their EDI invoice format document "Purchase Invoice Standards".
Does an invoice have to include a PO number?: Not by law. GOV.UK's list for every invoice and HMRC's list for VAT invoices do not mention a purchase order number. Some large buyers ask for one in their own terms: NHS Supply Chain (2025) its PO number, and Wickes (2022) and Travis Perkins (2021) the PO number or a four-digit cost centre number, with one PO number per invoice.
Why might a retailer query an invoice?: Because its details do not match what was received. Wickes (2022) and Travis Perkins (2021), in the same wording, look for an exact match with the products or services received, in terms of quantity, quality, price and fulfilment, and raise a Discrepancy Advice if there are inconsistencies. Transalis's EDI invoice guide explains how invoices are matched.

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