My niece is self-employed. I am filing her T1 return. When does it need to be filed? When do the taxes have to be paid?

Thank you for choosing TurboTax. Self-employed individuals have until June 15 to file their tax returns. However, any balance owed must still be paid by April 30. If you have self-employment income, consider preparing your tax return well before April 30 to calculate if you have a balance owed. This helps to avoid late-payment penalties. To discourage late filers, the CRA charges a late filing penalty of five percent of your balance owed plus an additional 1 percent for each month the return is late. This fee is added to the compound daily interest that begins accruing on the balance on its due date.

Income tax filing and payment deadlines for the 2020 tax year: CRA and COVID-19 

When Taxes Are Due In Canada