Should accountants write to clients about e-invoicing now?

A short, factual letter now is reasonable: the April 2029 date and the Peppol network are confirmed, and HMRC's research found SMEs see their accountant as a first port of call. Promise a fuller update once the Budget 2026 roadmap is published on 28 October 2026.

Can I put these templates on my practice website or send them to clients?

Yes. They are free to copy, edit and send, including commercially, as long as you credit einvoices.uk somewhere in the material, for example in a footer.

Do non-VAT-registered clients need to do anything?

The mandate applies to VAT invoices, and the government has said many of the smallest businesses that are not VAT-registered will not be obliged to adopt e-invoicing. Whether they will need to receive e-invoices has not been confirmed. Clients close to the £90,000 VAT threshold should plan as if they will be in scope.

Should the letter recommend a software product?

Keep the letter neutral and discuss software in a separate conversation. What suits a client depends on their current system, invoice volumes and customers.

E-invoicing client letter template for UK accountants

Below are three editable client letters about UK e-invoicing, one for each common client type, plus a short email version. Each states only what is confirmed as of 20 October 2026, names no software product, and links to GOV.UK. Copy the text, replace the [square brackets] and send it on your own letterhead.

HMRC's March 2026 research found that SMEs see their accountants and software providers as their first port of call for e-invoicing, not HMRC. The consultation response says accountants "would play a vital role" in communicating the change. A short letter now, followed by a fuller update after the Budget 2026 roadmap on 28 October 2026, meets that expectation without getting ahead of the facts.

Free to reuse. You may copy, edit and send these templates, including on your practice website, with a credit to einvoices.uk. They are general information, not tax advice; adapt them to your engagement terms.

Before you send: what is confirmed

Paste this box into any letter, or attach it. Check it against our mandate page on the day you send, because the roadmap may change it.

UK e-invoicing: confirmed as of 20 October 2026

From April 2029, VAT invoices for business-to-business and business-to-government sales must be issued as e-invoices. (Budget 2025; consultation response, 26 November 2025)

An e-invoice is structured data sent between accounting systems. PDF, Word and emailed invoices do not count.

The model is decentralised: businesses choose their own software or provider.

Peppol will be "the core interoperability network for e-invoicing in the UK". (Tax update 2026, 23 June 2026)

No real-time reporting to HMRC at launch.

A government roadmap is due at Budget 2026 on 28 October 2026.

Not yet confirmed: the exact data format, penalties, the position of businesses that are not VAT-registered, and any government support.

Letter 1: VAT-registered small business

[Practice name] [Date]

Dear [Client name],

E-invoicing: what is changing for [Business name] from April 2029

We are writing to let you know about a change to how VAT invoices will work in the UK, so that you have plenty of time to prepare.

What is changing. The government has confirmed that from April 2029, VAT invoices sent to other businesses and to the public sector must be issued as e-invoices. An e-invoice is not a PDF or an emailed invoice. It is information sent directly from your accounting software to your customer's software, usually without anyone retyping it. The government has said invoices will travel over a network called Peppol, and that businesses will be able to choose their own software provider.

What this means for you. As you are VAT-registered and sell to other businesses, the April 2029 requirement is expected to apply to you. You will also be receiving e-invoices from your suppliers into your software.

What is not yet known. HMRC has not yet published the full technical details, any penalties or the exact steps. The government will publish a roadmap on 28 October 2026, and we will write to you again once we have reviewed it.

What we suggest now. You do not need to buy anything yet. In the meantime, it would help if you could:

tell us which software you use to raise invoices and record bills, if we do not already know;

make sure your customer records hold each customer's full legal name, address and VAT number; and

note any customers, such as the NHS or larger companies, who already ask you to send invoices through a portal or network.

We will review your current setup with you [at your next review / before date] and agree a plan well ahead of April 2029.

If you have any questions, please contact [name] on [phone] or [email].

Yours sincerely,

[Name] [Practice name]

Background: GOV.UK, Promoting electronic invoicing: consultation response. Template adapted from einvoices.uk.

Letter 2: larger business with an ERP or several systems

[Practice name] [Date]

Dear [Finance director name],

UK mandatory e-invoicing from April 2029: planning for [Company name]

As part of our advisory work, we want to flag the UK's mandatory e-invoicing programme, which is likely to affect your finance systems and processes.

Confirmed position (as of [date]). From April 2029, all VAT invoices for business-to-business and business-to-government supplies must be issued as e-invoices. The government has confirmed a decentralised model, with Peppol as the core interoperability network, and no real-time reporting to HMRC at launch. It has said it will continue to engage with stakeholders on legacy systems that cannot interoperate in the future system.

Why it matters to you. E-invoicing affects both sales invoicing and accounts payable. For a business of your size, the work typically involves your ERP or billing system, any EDI links or customer portals you use today, supplier master data and approval workflows. Lead times for system changes are often longer than for the regulatory detail itself.

Still to be confirmed. The UK data specification, transitional rules, penalties and any requirements for software and service providers. The government's roadmap is due on 28 October 2026.

Suggested next steps.

Nominate an owner for e-invoicing within finance and IT.

Ask your ERP and billing system providers, in writing, for their UK Peppol plans and dates.

List your invoice flows: sales, purchases, self-billing, credit notes, intercompany and any reverse charge or multi-currency invoices.

Identify customers and suppliers already using Peppol, including any public sector customers.

Budget for the project in your [year] plans.

We would be happy to [run a short scoping session / review the VAT aspects of your plan]. Please contact [name] to arrange a time.

Yours sincerely,

[Name] [Practice name]

Background: GOV.UK, Tax update 2026 summary. Template adapted from einvoices.uk.

Letter 3: client who is not VAT-registered

[Practice name] [Date]

Dear [Client name],

E-invoicing from 2029: does it affect you?

You may have seen news that e-invoicing will become mandatory in the UK. We want to explain where you stand.

The rule applies to VAT invoices. From April 2029, VAT invoices sent to other businesses and the public sector must be issued as e-invoices. As [Business name] is not currently registered for VAT, you do not issue VAT invoices. The government has said that many of the smallest businesses that are not required to register for VAT, and choose not to, "will not be obliged to adopt this technology".

What is not yet confirmed. The government has not yet said whether businesses that are not VAT-registered will need to receive e-invoices from their suppliers, or how they might take part voluntarily. More detail is expected in a roadmap on 28 October 2026.

When this could change for you. If your taxable turnover goes over the VAT registration threshold (currently £90,000 in a rolling 12 months), or you choose to register, e-invoicing would apply to your VAT invoices. [We estimate your current turnover at £[X] / Your turnover is close to the threshold], so [this is unlikely to affect you soon / we should plan for it].

What we suggest. No action is needed now. If you are choosing new invoicing software anyway, it is worth asking whether it can send and receive e-invoices over Peppol.

We will let you know if anything changes. Please contact [name] with any questions.

Yours sincerely,

[Name] [Practice name]

Background: GOV.UK, Register for VAT. Template adapted from einvoices.uk.

Short email version

Subject: E-invoicing becomes mandatory for VAT invoices from April 2029

Hi [name],

A quick heads-up: from April 2029, VAT invoices to other businesses and the public sector must be sent as e-invoices. That means structured data sent from your software to your customer's software over a network called Peppol, not a PDF by email.

You don't need to do anything yet. The government publishes its detailed roadmap on 28 October 2026, and we'll be in touch afterwards with what it means for you. In the meantime, it helps to make sure your customer records include full legal names, addresses and VAT numbers.

Any questions, just reply to this email.

[Name], [Practice name]

Tips for using these letters

Date everything. Write "as of [date]" next to any statement of what is confirmed.
Do not promise timelines that HMRC has not published, such as phased dates by business size. None has been announced.
Keep software advice separate. If clients ask what to use, our software checklist and dated software status table give a neutral starting point.
Segment your client list with the scope checker logic: VAT-registered and selling B2B or B2G, VAT-registered but B2C only, and not VAT-registered.
Plan the follow-up for after 28 October 2026. See our guide for accountants for a practice-wide plan.

What to do now

Pick the letter for each client segment and add your details.
Check the "confirmed" box against the mandate page on the day you send.
Diary a second mailing for after the Budget 2026 roadmap.

Spotted a mistake? Report an error. einvoices.uk is an independent publication and is not affiliated with HMRC. Details of the mandate may change; check the sources and official GOV.UK guidance before acting.