Invoice
Learn what an invoice is, what an Irish VAT invoice must include and when e-invoicing becomes mandatory.
Published Tuesday 27 October 2026
Table of contents
Key takeaways
- An invoice is a seller’s request for payment for goods or services, showing what was supplied, the amount owed, and when and how to pay
- An Irish VAT invoice must show Revenue’s mandatory fields, including the supplier’s VAT number and VAT amount, and issue within 15 days of month end
- Under Revenue’s announced plans, structured e-invoicing starts on 1 November 2028 for large corporates, and all businesses in Ireland must be able to receive e-invoices
- A quote estimates a cost before work, a receipt proves payment afterwards, and a pro forma invoice previews costs before a sale is agreed
What is an invoice?
An invoice is a document a seller issues to request payment for goods or services supplied. It shows what was provided, the amount owed, and when and how to pay.
A clear invoice usually includes:
- the quantity of goods or services supplied
- the rate or unit price
- the total cost due
- a description of what was provided
- when and how to pay
Handy resources
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Disclaimer
This glossary is for small business owners. The definitions are written with their requirements in mind. More detailed definitions can be found in accounting textbooks or from an accounting professional. Xero does not provide accounting, tax, business or legal advice.
Once it’s ready, you can hand it over by post or email, and Xero’s guide to sending invoices to customers walks through the practical steps.
What invoice payment terms mean
Payment terms tell your customer how long they have to pay and set expectations on both sides. Getting them right keeps money moving into the business on a schedule you can plan around.
‘Net 14 days’, for example, means the full amount is due within 14 days of the invoice date. Clear terms help you forecast cash flow and stay on top of the money your customers owe you. They also give you a firm reference point when you need to follow up on late payments.
Invoice vs quote
It’s easy to mix up a quote and an invoice, so it helps to see where each one sits in a sale.
A quote is an estimate of what a job will cost, sent before any work is agreed. An invoice is the actual charge for goods or services already supplied. When you receive an invoice from a supplier, it’s a purchase invoice; when you issue one to a customer, it’s a sales invoice.
E-invoices and VAT invoices
As invoicing goes digital, two invoice types matter for Irish businesses: the e-invoice and the VAT invoice. You can already create and send documents online with Xero’s online invoicing, so it helps to know how each type works.
A true e-invoice is a structured electronic file that meets the EU standard EN 16931. Accounting systems usually exchange it over networks such as the Peppol network, so it can be processed automatically. Emailing a PDF or a scanned paper invoice isn’t a structured e-invoice, even though it travels electronically.
A VAT invoice is the document a VAT-registered (accountable) trader issues to record a taxable supply, as required by Irish VAT law. It sets the supplier’s VAT liability and lets a VAT-registered customer reclaim the VAT charged through their VAT returns.
Each VAT invoice must carry a set of prescribed details, listed in the next section. It must also issue within 15 days of the end of the month in which the supply is made. This obligation covers supplies to other VAT-registered businesses and the other recipients Revenue specifies, rather than every customer.
What must an Irish VAT invoice include?
Once you register for VAT, Revenue sets out the information required on a VAT invoice. Each one you issue must show:
- the supplier’s name, address and VAT number
- a unique sequential invoice number
- the date of issue and the date of supply
- the customer’s name and address, plus their VAT number where relevant
- a description and quantity of the goods or services
- the VAT-exclusive amount, VAT rate and VAT amount
Ireland’s e-invoicing timeline
Structured e-invoicing is arriving in stages, so the date that matters to you depends on your size and where you trade. The EU’s VAT in the Digital Age (ViDA) package was adopted in March 2025.
According to Revenue’s phased domestic rollout, structured e-invoicing becomes mandatory for intra-EU business-to-business (B2B) transactions from 1 July 2030, with earlier phases at home. These dates are Revenue’s announced plans, and the Finance (No. 2) Bill 2026, published on 19 October 2026, would give them a legal basis once it’s enacted.
- 1 November 2028:large corporates in Revenue’s Large Corporates Division must issue domestic B2B e-invoices, and all businesses in Ireland must be able to receive them
- November 2029: the requirement extends to VAT-registered businesses trading within the EU
- 1 July 2030: Irish rules fully align with ViDA for intra-EU B2B transactions
- Format: e-invoices follow EN 16931, and Revenue plans to use existing infrastructure such as the Peppol network
Pro forma invoice
Some sales call for a preliminary document before anything is finalised, and that’s where a pro forma invoice comes in.
A pro forma invoice is a preliminary estimate sent before a sale is finalised, so a buyer can review costs, arrange finance or clear customs. It isn’t a demand for payment, and it isn’t a valid VAT invoice. To see how it fits alongside other invoice types, read Xero’s overview of what an invoice is.
Invoice vs receipt
Buyers and sellers exchange more than one document around a single payment, so it’s worth separating the two you’ll use most.
An invoice is a request for payment, issued before the customer pays. A receipt is proof that payment has been received, issued after the money changes hands. Keep both for your records, and you can start with Xero’s free receipt template.
Simplify invoicing with Xero
Chasing payments and formatting documents by hand eats into time you’d rather spend on the business. With Xero you can create, send and track invoices online, set up automatic reminders, and see what you’re owed at a glance.
If you’d like a hand with VAT or setting up your invoicing, you can find a certified accountant or bookkeeper in the Xero Advisor Directory. Start today and get one month free to try it on your own invoices.
FAQs on invoicing
Still have questions about invoices? These quick answers cover the details Irish small business owners ask about most.
Is an invoice a legal document?
An invoice records what a customer owes for goods or services you’ve supplied, and you should keep copies for your records. A VAT invoice also carries specific requirements under Irish VAT law.
What’s the difference between an invoice and a bill?
They’re the same document seen from opposite sides: you issue an invoice to a customer, and that customer records it as a bill to pay. The wording usually depends on who’s holding it.
Do I have to issue a VAT invoice?
Only if you’re VAT-registered and supplying other VAT-registered businesses or the other recipients Revenue lists. Sales to private consumers don’t usually need a full VAT invoice.
Can I send an invoice as a PDF?
Yes, you can email a PDF for a customer to read and pay. A structured e-invoice is a separate, machine-readable file exchanged between systems, so a standalone PDF doesn’t meet that definition.
When does e-invoicing become mandatory in Ireland?
Under Revenue’s announced plans, the first phase starts on 1 November 2028, when all businesses in Ireland must be able to receive structured e-invoices. Check that your accounting software can accept e-invoices well before that date.