Information You Need to Supply for Professional Help with Your Tax Return

[Updated November 2025]: If you’re self-employed in the UK and earn more than £1,000 after allowable deductions, you need to file a self-assessment tax return each year. It’s not only the self-employed, though. If you are on a higher income* or receive untaxed income from things like property rental, tips, commission, savings, investments, dividends, or foreign income, you also have to submit a return. Partners in business partnerships and those who made a capital gain resulting in Capital Gains Tax (CGT) also need to submit a return.
If you do have to fill in a self-assessment tax return, getting all the tax return fields filled in properly and the figures right can sometimes be difficult. That’s where professional help from companies like Taxfile is worth its weight in gold. But what information will your accountant or tax advisor need from you? In today’s guide, we’ll explain exactly what you’ll need to supply.








