UK Invoice Essentials in 2026: everything you should know about

Invoices do more than request payment – they create the digital records you’ll rely on for Making Tax Digital for Income Tax Self Assessment (MTD for ITSA). From 2026, many sole traders and landlords will need to keep those records digitally and send quarterly updates through compatible software. MTD focuses on how you record and submit data, not your invoice’s visual design. The information on your invoice still matters, because it drives accurate updates and a smooth year-end.

This guide explains what a UK invoice must include, how to set payment terms that match UK rules, lawful late-fee wording, and how invoices plug neatly into an MTD-ready workflow. 

MTD for ITSA and Invoices: Easy Invoicing for Sole Traders and Landlords

Under MTD for ITSA you keep digital records (date, amount, category) for your business or property income, send quarterly updates from compatible software, and complete your end-of-year submission through that software. MTD doesn’t prescribe an invoice layout; it requires that your records are digital and, if you use spreadsheets, that figures flow to HMRC via digital links (no copy–paste).

Required fields on a UK Invoice 

GOV.UK sets out what invoices should contain so customers understand what they owe and why. Include: a unique invoice number; your business name and address; the customer’s name and address; what you’re charging for (clear line descriptions); the supply date; the invoice date; the amounts charged; VAT amount if applicable; and the total due.

• Sole traders: show your name (and any trading name) plus an address for legal documents.

• Limited Companies: show the registered name; if you list any directors on the invoice, you must list all of them.

If you are VAT-registered, follow HMRC’s VAT-invoice rules as well (for example, VAT number, tax point, rate/amount). This article focuses on ITSA, but VAT rules still apply when relevant.

Payment Terms that Work (clear for invoice for small business users)

Set payment terms in writing on every invoice. For business-to-business transactions, the UK framework says agreed payment dates should usually be within 60 days (or 30 days when the payer is a public authority). You can agree longer B2B terms only if they’re fair to both sides. If nothing is agreed, an invoice becomes “late” 30 days after the invoice date or delivery of the goods/services – whichever is later.

Late-Fee Wording that’s Lawful and Effective

For late B2B payments you may charge statutory interest at 8% above the Bank of England base rate, plus fixed debt-recovery costs – unless you’ve agreed a different rate in your contract (you cannot set a lower rate for public authorities). A clear clause keeps things simple:

“Payment terms: 14 days from invoice date. We reserve the right to charge statutory interest on late B2B payments at 8% above the Bank of England base rate and to claim fixed debt-recovery costs, in line with UK late-payment rules.”

Use this in your standard terms and refer to those terms on each invoice.

MTD Deadlines 2026–27

MTD for ITSA becomes mandatory by income band:

• From 6 April 2026: qualifying income over £50,000 (based on the 2024–25 return).

• From 6 April 2027: qualifying income over £30,000 (based on 2025–26).

Quarterly updates have fixed deadlines every year: 7 August, 7 November, 7 February, 7 May. The 31 January filing/payment date still applies for the year-end submission through software.

How Invoices Feed Your MTD Records 

Treat each invoice as the start of a clean digital trail: issue the invoice with the required fields → capture it digitally (software, or spreadsheet with bridging) → categorise the income to the right business/property source → let your software roll up quarter totals for submission → make year-end adjustments and submit via software by 31 January.

When invoices are complete and searchable, quarterly updates are quicker and you need fewer corrections later.

Where EasyInvoice Fits 

EasyInvoice is being built around HMRC’s latest MTD for ITSA rules so invoices flow into compliant digital records, quarterly updates are straightforward, and year-end is a tidy-up—not a rebuild. If you prefer spreadsheets, bridging support (with digital links) is on the roadmap. If you want an all-in-one approach, the app guides setup, categories, and deadline planning so you stay on top of MTD without changing how you work overnight.

Join the EasyInvoice Waiting List for early access and a smoother start

Key Takeaways

• MTD for ITSA changes how you record and submit data, not your invoice design.

• Include the required invoice fields so totals map cleanly into your digital records.

• Set fair, clear payment terms and use lawful late-fee wording.

• Map the fixed quarterly deadlines and keep invoices flowing into your software to avoid a year-end scramble.