Completing a tax return can feel overwhelming, especially if you are unsure what information you need to provide. Whether you are self-employed, a landlord, or an employee, having the right records makes the process faster, more accurate, and stress-free.
In this guide, we explain what information is required to complete a tax return and how upcoming changes like Making Tax Digital (MTD) may affect you.
What Should Be Included in a Tax Return?
Your tax return must include all taxable income and capital gains for the relevant tax year. This ensures HMRC can calculate the correct amount of tax you owe (or refund you are due).
Common Information Needed for a Tax Return
You may need some or all the following details when completing your Self-Assessment tax return:
- Self-employment income and expenses
Used to calculate your trading profit or loss for the year. - Property rental income and expenses
Required to work out your rental profit or loss. - Employment and pension income
Including P60, P11D, and P45 forms from any jobs held during the year. - Bank and building society interest
Interest certificates or statements showing savings income. - Pension contributions
Especially contributions made to relief-at-source pension schemes. - Capital gains information
Details of any chargeable gains from selling assets such as property, shares, or investments.
Do You Need to Send Documents to HMRC?
You do not need to submit original documents with your tax return. However, HMRC may ask for evidence later if they have questions about your return.
Keeping accurate records helps you:
- Prove the figures on your tax return.
- Show that you took reasonable care.
- Avoid penalties or unnecessary stress.
If you are self-employed or earn income from property, you must be able to clearly show how you calculated your profit or loss.
What Records Should You Keep?
To support your tax return, it is important to keep detailed financial records, including:
- Invoices for work completed.
- Receipts for business or rental expenses
- Bank statements
- Letting agent statements (or rental income records if self-managed)
- Records of private use of business assets (for example, mileage logs for vehicles used for both business and personal purposes)
Good record-keeping not only supports your tax return but also saves time when filing future returns.
Making Tax Digital for Income Tax (MTD ITSA)
From April 2026, Making Tax Digital for Income Tax Self-Assessment (MTD ITSA) will be introduced. This new system will require eligible taxpayers to:
- Keep digital records.
- Submit quarterly updates to HMRC.
- Use MTD-compatible software.
MTD ITSA will apply to certain self-employed and landlords .
To find out when it becomes mandatory for you:
- Read our detailed blog on Making Tax Digital
- Use our MTD ITSA calculator to know when it will be mandatory for you..
Final Thoughts
Knowing what information, you need to complete a tax return can make the entire process simpler and less stressful. With accurate records and early preparation, you can file confidently and stay compliant with HMRC requirements.
If you need help preparing your tax return or understanding how Making Tax Digital will affect you, professional advice can save you time, money, and worry.
At GM Accountants & Tax Consultants, our team of qualified accountants can support and guide you with Making Tax Digital for Income Tax Self-Assessment (MTD ITSA) and other tax matters, at competitive and affordable prices. Please feel free to contact us for expert advice. If you are unable to visit our office, we can arrange a video call at a time that suits you. For further information, email us at admin@gmtaxconsultants.co.uk or call us on 020 3773 4123.
Disclaimer:
The information provided in this blog is for general informational purposes only and does not constitute professional accounting or tax advice. As individual circumstances may vary, readers are advised to contact us directly for advice tailored to their specific financial or tax situation.
