To send a tax return, you must be registered for Self Assessment.
You must send a tax return if, in the last tax year (6 April to 5 April), you were:
self-employed as a ‘sole trader’ and earned more than £1,000 (before taking off anything you can claim tax relief on)
a partner in a business partnership
You will not usually need to send a return if your only income is from your wages or pension.
But you may need to send one if you have any other untaxed income, such as:
money from renting out a property
tips and commission
income from savings, investments and dividends
You can always check if you need to send a tax return if you’re not sure.