Which child benefit? If you are referring to the Canada Child Benefit (CCB), it’s not taxable, so you don’t need to report it on your income tax. You do need to file a tax return to be able to receive it, though.
If you want to apply for it, and you have a Canada Revenue Agency (CRA) My Account, you can go to the Benefits and Credits section there and click “Add A Child”. This will allow you to start the process for enrolling in the Canada Child Benefit program. You can login or sign up for My Account here: https://www.canada.ca/en/revenue-agency/services/e-services/e-services-individuals/account-individua...
You can also fill in the form RC66 Canada Child Benefits Application and mail it in to apply for the CCB. Download the form here: https://www.canada.ca/en/revenue-agency/services/forms-publications/forms/rc66.html
