HMRC recognised HMRC recognised agent software

How to File
Self Assessment
as an Agent

A complete guide for accountants and tax agents to manage and submit Making Tax Digital (MTD) for Income Tax Self Assessment (ITSA) updates and declarations on behalf of clients using HMRC-recognised software.

Read the Guide
Manage multiple clients Quarterly updates HMRC submission & records
8 steps to HMRC
Multi-Client Dashboard
Manage all ITSA clients in one place
Quarterly Updates
Submit income & expense updates
EOPS Completed
Finalise end-of-period statements
Final Declaration Sent
Submitted to HMRC with receipt
For Accountants & Tax Agents

What Is MTD for ITSA for Agents?

Making Tax Digital (MTD) for Income Tax Self Assessment (ITSA) requires agents to maintain digital records and submit updates for clients throughout the year instead of a single annual return.

As an agent, you will submit quarterly updates, complete an End of Period Statement (EOPS), and file a Final Declaration for each client using HMRC-recognised software.

Submit quarterly income & expense updates
Complete End of Period Statement (EOPS)
File Final Declaration to HMRC
Manage all clients from one dashboard

What You Need Before You Start

Government Gateway

Agent Government Gateway user ID and password

Agent Services Account

HMRC ASA set up and active for MTD services

Agent Reference Number

Your unique ARN from HMRC agent registration

Client Authorisation

Digital authorisation from each client via HMRC

1 HMRC Agent
2 Sign Up
3 Authorise
4 Add Client
5 Records
6 Quarterly
7 EOPS
8 Declaration
Step-by-Step Agent Guide

ITSA Agent Filing Process in 8 Steps

Follow these 8 steps to manage Making Tax Digital (MTD) for Income Tax Self Assessment (ITSA) for your clients — from HMRC agent setup to quarterly updates and final declaration.

1

Register as HMRC Agent

To act on behalf of clients, you must be registered with HMRC as an agent:

  • Create Agent Services Account (ASA)
  • Get Agent Reference Number (ARN)
  • Link Government Gateway credentials
  • Agent contact information
2

Sign Up on 11taxassist

Create your free account at 11taxassist and select Agent as your user type:

  • Enter your Agent Reference Number (ARN)
  • Connect to your HMRC Agent Services Account
  • Add your agent business details
3

Get Client Authorisation

You must obtain digital authorisation before accessing client data:

  • Log in to your Agent Services Account
  • Select “Ask a client to authorise you”
  • Enter the client’s NINO (national insurance number)
  • HMRC sends a digital authorisation link
  • Client approves the request online
4

Add Client & Income Sources

After authorisation, add client profile and select income types:

  • Self-employment
  • UK property income
  • forein property income
5

Maintain Digital Records

Record client income and expenses digitally as required by MTD: sales, purchases, allowable expenses, and adjustments.

6

Submit Quarterly Updates

Send quarterly summaries of income and expenses to HMRC for each income source using MTD-compatible software.

7

Submit EOPS

Submit the End of Period Statement (EOPS) to finalise business income after adjustments like capital allowances.

8

Final Declaration

Submit the final declaration to HMRC confirming all income sources, tax calculations, and allowances — completing the ITSA filing process.

Client Authorisation

How to Authorise Clients for MTD ITSA

HMRC’s digital authorisation process replaces the traditional 64-8 paper form for MTD services. As an agent, you must request authorisation through your Agent Services Account before you can file ITSA returns on a client’s behalf.

Each client must authorise you separately for MTD ITSA
Authorisation links expire after 21 days
Clients need their own Government Gateway to approve

HMRC Digital Authorisation Steps

1
Log in to your Agent Services Account

Access your HMRC ASA using your agent Government Gateway credentials.

2
Select “Ask a client to authorise you”

Choose the MTD for ITSA service from the available options.

3
Enter the client’s NINO (National Insurance Number)

HMRC generates a unique authorisation invitation link.

4
Send the link to your client

Share the HMRC invitation link with your client via email or secure message.

5
Client approves the request

Your client logs in with their own Government Gateway and approves your authorisation request. You can now file on their behalf.

ITSA Quarterly Filing

Review Every Figure of each clients Before You Submit

Before clients quarterly return is sent to HMRC, you'll see a clear breakdown of clients self-employment income and every expense line. The system auto-calculates clients taxable profit — no manual maths needed.

Automatic income & expense calculations
Allowable and disallowed expenses shown side by side
Taxable profit calculated instantly from clients figures
HMRC confirmation receipt with reference number
Covers SE, UK property and foreign property filings

Quarterly Filing

Self-employment · Q2 2024–25
Business Smith Consulting
NI Number AB123456C
Period Apr – Jun 2024
Self Employment Income
Sales (Turnover)£17,000
Other Business Income£1,500
Total Income£18,500
Self Employment Expenses
Expense Category Total Disallowed
Wages & Staff Costs£1,200£0
Car & Travel Expenses£480£120
Premises & Insurance£650£0
Advertising Costs£300£50
Professional Fees£900£0
Other Business Expenses£700£80
Total Expenses £4,230 £250
Templates

HMRC-Aligned ITSA Excel Templates

Download our pre-built templates for each client. Enter the figures, upload, and the system does the rest — maintaining a fully digital link as required by MTD.

Self-Employment Template

Record business income and allowable expenses for sole traders. Includes categories aligned with HMRC requirements such as turnover, cost of goods, expenses, and adjustments for accurate profit calculation.

Property Income Template

Track UK and foreign property income with HMRC-compliant structure. Record rental income, expenses, and adjustments separately for UK and overseas properties as required under MTD for ITSA.

Comparison

Agent vs Individual ITSA Filing

Not sure which account type you need? Compare filing your own Income Tax under Making Tax Digital (MTD for ITSA) vs filing as an agent for clients.

Feature Individual Agent
File own ITSA returns
File ITSA for multiple clients
Manage multiple income sources (per client)
HMRC Agent Services Account (ASA) required
Digital client authorisation required
Quarterly updates submission
End of Period Statement (EOPS)
Final Declaration submission
Automatic tax calculations
Direct HMRC MTD submission
HMRC receipt & downloadable records
Price per submission £5.99 £5.99
Why 11taxassist for ITSA Agents

Built for MTD ITSA Accountants & Agents

Everything you need to manage Making Tax Digital (MTD) for Income Tax — from quarterly updates to final declarations — all in one secure, HMRC-compliant platform.

HMRC Recognised Software

Fully compliant with HMRC MTD for ITSA requirements. Submit updates and declarations directly via secure HMRC APIs.

Unlimited Client Management

Manage multiple clients, income sources, and obligations from a single agent dashboard with ease.

Quarterly Updates Made Easy

Submit quarterly income and expense updates for each client in line with MTD ITSA rules.

Smart Tax Calculations

Automatic calculation of taxable profits, adjustments, and estimated tax liability with built-in error checks.

EOPS & Final Declaration Support

Easily complete End of Period Statements (EOPS) and final declarations to close the tax year accurately.

Secure & Compliant

Bank-level encryption, secure authentication, and full compliance with HMRC digital record-keeping standards.

ITSA Agent Filing — Just £5.99 per Client Submission

No monthly subscriptions, no hidden fees. Pay only when you submit quarterly updates, EOPS, or final declarations for your clients. Regular price £15.99 — you save £10.00 (63% off).

Includes HMRC-recognised MTD ITSA software, unlimited client management, digital record support, automatic tax calculations, error validation, direct HMRC submission, and downloadable confirmation records.

Frequently Asked Questions

Frequently Asked Questions About Online VAT Filing & MTD Self Assessment

Find answers to the most common questions about our online tax filing service.

Is your software recognised by HMRC?
Yes. Our software is an HMRC-recognised MTD filing solution, allowing you to submit VAT returns and Self Assessment updates directly to HMRC through their official API.
Do I need to sign up for MTD with HMRC before filing?
Yes. Before submitting returns through our software, you must first sign up for MTD with HMRC and authorise our software to connect to your HMRC account via Government Gateway.
How secure is my personal information?
We use bank-level 256-bit SSL encryption and follow strict UK GDPR standards. All your data is stored securely in UK-only data centres and never shared with third parties.
Can agents use 11taxassist on behalf of clients?
Yes. Tax agents can use our HMRC-recognised platform to file both VAT returns and MTD quarterly updates plus Final Declarations on behalf of clients. Agents need an Agent Services Account (ASA) and must be authorised by their client through HMRC's digital handshake process.
Is 11taxassist a registered UK company?
Yes. 11taxassist Limited is a UK-registered company (Company Number: 16416027) registered with Companies House. Our registered office is at 6 Alexander Court, Baker Street, Reading, England, RG1 7XZ.
Do you offer a money-back guarantee?
Yes. If your return fails to submit to HMRC due to a fault on our software, we will refund your filing fee in full — no questions asked. Our 99.8% success rate speaks for itself.
What is Making Tax Digital (MTD) for VAT?
Making Tax Digital (MTD) for VAT is an HMRC initiative requiring VAT-registered businesses to keep digital VAT records and submit VAT returns using MTD-compatible software. It became mandatory for all VAT-registered businesses from April 2022, unless exempt.
How often do I need to file VAT returns?
Most VAT-registered businesses must submit quarterly VAT returns (4 times per year). Each quarterly return covers a 3-month period and must be submitted within one month and 7 days of the end of the quarter.
Who must follow the MTD for VAT rules?
All VAT-registered businesses must comply with MTD rules, regardless of turnover, unless they have an exemption approved by HMRC. New VAT-registered businesses are automatically enrolled. Those below the VAT threshold may opt in voluntarily.
What are the requirements for MTD-compatible VAT filing?
  • Keep VAT records digitally using MTD-compatible software
  • Submit VAT returns electronically via an API (not the HMRC portal)
  • Maintain digital links between all data sources to avoid manual entry
  • Preserve digital VAT records for at least six years
Can I upload my VAT data from a spreadsheet?
Yes. 11taxassist supports Excel spreadsheet upload for VAT returns. You can prepare your VAT figures in a spreadsheet and upload them directly into our platform. The software will validate the data and submit it to HMRC via the MTD API — maintaining a fully digital link.
How do I sign up for Making Tax Digital for VAT?
HMRC automatically signs up VAT-registered businesses for MTD unless exempt. To file VAT returns under MTD, you'll need a Government Gateway account and VAT registration number. Agents must use an Agent Services Account (ASA) to manage clients' VAT returns.
What is MTD for Self Assessment (MTD for ITSA)?
MTD for Income Tax Self Assessment is a new HMRC initiative requiring sole traders and landlords to keep digital records and submit quarterly updates of their income and expenses using MTD-compatible software, followed by a Final Declaration at year-end. It replaces the traditional annual Self Assessment return for those who qualify.
Who needs to use MTD for Self Assessment?
You'll need to use MTD for Income Tax if you are a sole trader or landlord registered for Self Assessment and your qualifying gross income from self-employment and/or property exceeds the threshold: over £50,000 from April 2026, over £30,000 from April 2027, and over £20,000 from April 2028. Partnerships will be included at a later date.
What counts as "qualifying income" for MTD?
Qualifying income is your combined gross income (turnover before expenses) from self-employment and property. This includes UK and overseas rental income. It does not include employment income, dividends, savings interest, or pension income.
How many submissions are required each year?
Under MTD for ITSA you must submit:
  • 4 Quarterly Updates (summaries of income and expenses)
  • 1 Final Declaration (replaces your annual Self Assessment return)
Total: 5 submissions per year.
What is a Final Declaration?
The Final Declaration replaces the traditional Self Assessment tax return for MTD users. After all four quarterly updates, you confirm all income sources are complete and accurate, add any additional income (employment, dividends, etc.), claim allowances and reliefs, and finalise your tax position. It must be submitted by 31 January following the end of the tax year.
What are the quarterly update deadlines?
Q1 (6 Apr – 5 Jul): due 7 August
Q2 (6 Jul – 5 Oct): due 7 November
Q3 (6 Oct – 5 Jan): due 7 February
Q4 (6 Jan – 5 Apr): due 7 May
Final Declaration: due 31 January (following year)
What are the penalties for missing MTD deadlines?
For 2026–27, HMRC will not apply late submission penalties for missing quarterly update deadlines (soft-landing period). However, penalties for late Final Declarations and late payments still apply from day one. From 2027–28, a points-based system applies: each missed deadline earns a penalty point, and after 4 points, a £200 fine per further missed deadline.
Am I exempt from MTD for Income Tax?
You may be exempt if you are digitally excluded (e.g. due to age, disability, or location without reliable internet). If exempt, you must still file Self Assessment in the traditional way. Check your eligibility using HMRC's online tool or contact HMRC directly.
What do I need to get started?
You'll need: a Government Gateway user ID and password, your National Insurance number, your Unique Taxpayer Reference (UTR), and details of your income sources. Register on 11taxassist, connect your HMRC account, and our software guides you through everything.
Do partnerships need to use MTD for Income Tax?
Not yet. HMRC has confirmed partnerships will be brought into MTD for Income Tax at a later date, but no timeline has been set. Currently only sole traders and landlords are required to comply.
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Company number: 16416027

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