Here are some basic tax deductions and reliefs that will show on your self-assessment tax return:

Personal Allowance:
Every taxpayer is entitled to a certain amount of tax-free income each year, known as the Personal Allowance. For the 2022/23 tax year, the Personal Allowance is £12,570.

Business expenses:
If you are self-employed, you can claim tax relief on certain business expenses

Trading losses:
If you are self-employed and make a loss in a tax year, you can offset this loss against your other income or carry it forward to future tax years.

Pension contributions:
If you make contributions to a registered pension scheme, you can claim tax relief on these contributions. The amount of tax relief you can claim depends on your marginal tax rate.

Charitable donations:
If you make donations to registered charities, you can claim tax relief on these donations. The amount of tax relief you can claim depends on your marginal tax rate.

Marriage Allowance:
If you are married or in a civil partnership, and one of you earns less than the Personal Allowance, the other partner may be able to transfer up to 10% of their unused Personal Allowance to the lower-earning partner.