E-invoicing guide for UK accountants and bookkeepers

Accountants and bookkeepers will be the first people many small businesses ask about e-invoicing. The short answer for your clients: VAT-registered businesses should plan to send and receive VAT invoices as e-invoices over Peppol from April 2029, and most will do it through the software you already help them run.

This guide sets out a practical approach for practices: how to triage a client list, what to check, and where the work (and the fee opportunities) are likely to be.

The position today

Confirmed:

• E-invoicing will be mandatory for VAT invoices from April 2029 (consultation response published with the Autumn Budget 2025).
• The UK is using a decentralised model, with invoices exchanged between businesses through service providers.
• Peppol is the network. The GOV.UK Tax update 2026 summary (23 June 2026) says: "The government has announced that the electronic procurement system Peppol will be the core interoperability network for e-invoicing in the UK."
• There will be no real-time reporting to HMRC alongside the mandate.

Not yet confirmed: the data standard, exemptions, any phasing, penalties, and treatment of receipts, simplified invoices and self-billing. The roadmap is due at Budget 2026 on 28 October 2026. The consultation response names tax professionals among the groups the government would engage from January 2026.

E-invoicing is not Making Tax Digital, but it will feel like it

Clients will confuse the two, so be clear:

	Making Tax Digital	E-invoicing
What it covers	Digital records and submitting returns to HMRC	How invoices are exchanged between businesses
Who receives the data	HMRC	The customer (via Peppol)
VAT	All VAT-registered businesses must keep digital records and file using software (VAT Notice 700/22)	VAT invoices from April 2029
Income Tax	Phased in from April 2026 (£50,000 qualifying income), April 2027 (£30,000) and April 2028 (£20,000)	Depends on VAT registration, not income

The overlap matters for workload. MTD for Income Tax thresholds drop to £20,000 in April 2028, one year before the e-invoicing mandate. Many sole trader clients will face software changes in both years. Where you are already moving a client to new software for MTD, check now that it will support Peppol e-invoicing, so they change once rather than twice. See e-invoicing vs Making Tax Digital.

Step 1: triage your client list

Pull a list from your practice software and tag each client:

Tag	Who	Action
A – in scope, issuing	VAT-registered, invoices businesses or public sector	Full readiness review
B – in scope, receiving	VAT-registered, mainly B2C sales, buys from VAT-registered suppliers	Receiving set-up; watch B2C rules
C – edge case	VAT groups, self-billing, construction reverse charge, Northern Ireland, Isle of Man, overseas	Flag; wait for roadmap detail
D – out of scope for now	Not VAT-registered	Note; revisit if they approach the VAT threshold

Links for the edge cases: VAT groups, self-billing, construction reverse charge, Northern Ireland, Isle of Man, non-VAT-registered businesses.

Step 2: review software, client by client

Group clients by the software they use. For each product, ask the vendor once and apply the answer across the group. Useful questions:

1. Will the product send and receive Peppol invoices and credit notes for UK VAT invoices?
2. Is the Access Point built in, partnered or customer-supplied? Is it a Peppol certified service provider?
3. Is it included in current plans or charged separately?
4. How are Peppol IDs assigned and registered for each client company?
5. How are rejected invoices shown to the user?
6. Can an accountant or bookkeeper user see incoming e-invoices for a client?

Do not rely on marketing pages. See how to check your accounting software's Peppol support.

Clients still invoicing from Word, Excel or a basic invoicing app are your priority group. They will need to move to software that can produce structured e-invoices; a PDF is not an e-invoice.

Step 3: data clean-up

Bookkeepers often know where the bad data is. Before April 2029, help clients:

• confirm their own legal name, address and VAT number in every system;
• verify customer VAT numbers with HMRC's Check a UK VAT number service;
• merge duplicate supplier and customer records;
• make sure VAT rates on items map to VAT category codes;
• record purchase order and buyer references for customers who need them.

Our master data clean-up guide has a full list.

Step 4: rethink bookkeeping workflows

E-invoicing changes the purchase side most. Supplier bills will arrive as data instead of PDFs, so time spent on data capture should fall. That changes what clients pay you for. Review:

• Bill capture. If you use a receipt-capture or scanning tool, ask how it will handle Peppol invoices alongside paper receipts.
• Approvals. Who approves bills, and where? E-invoices make approval workflows easier to enforce.
• Records. HMRC says VAT records should generally be kept for at least six years (VAT Notice 700/21). Confirm where the e-invoice itself is stored, not just the posted transaction. See e-invoice archiving.

Services you could offer

• E-invoicing readiness reviews based on our readiness checklist
• Software selection and migration, timed with MTD for Income Tax where possible
• Customer and supplier data clean-up
• Help with validation errors in the first months (see common Peppol validation errors)
• Training for client staff who raise invoices

Price these on your own costs; there are no reliable market rates yet.

What to do now

Run the triage on your client list this month, so you know your exposure before the roadmap on 28 October 2026. Then write to your main software vendors with the six questions above, and add an e-invoicing line to your MTD client letters. Keep an eye on the timeline and HMRC's guidance as it is published.