Income tax applies to most types of income, including the salary you earn from your job, profit earned from your business, pensions, and even the rent you receive if you’re a landlord. Corporations, estates and other types of entities are also required to pay tax on their profits.
You might not have to pay income tax on all of your income, because most people qualify for one or more types of tax-free allowances or tax credits. An allowance is the amount of taxable income you can earn before paying income tax (more on that below).