The T4 tax slip is used by your employer to show what you have been paid before deductions, as well as your CPP, QPP, EI contributions from your paycheque during the tax year. It may also indicate eligibility for deductions you can claim against your employment income. Income from pensions and other types of income are reported on a T4A tax form. This form must be completed each year and employers must send them by the end of February. If you change jobs, make sure your former employer has a current address so they can mail you a T4.