There is no single place to put losses on the self-employment form. You enter your income & then your expenses, and if your expenses are greater than your income, you end up with a loss. If you are day trading, you would enter your stocks as inventory - how much you started with, how much you bought and how much your inventory was worth at the end of the year.
TurboTax Online for 2021 and earlier are no longer available, so you can't use Refile to amend your returns for 2021 or 2018. But, you can still can make the adjustments using the Canada Revenue Agency’s (CRA) My Account service or you can print & mail a T1-ADJ T1 Adjustment Request.
