A child travel consent form or travel consent letter is merely a letter of permission from the legal guardian or parent of a child that allows a child to travel to a foreign country. There is no standard form that is required for this. Additionally, different countries ask for different forms of permission. Please check with the destination country for their specific requirements.
Various countries may have different ages of adulthood. Even in Canada, the age of majority is 18 or 19 years depending on the province or territory. If your child is looking to travel, it is wise to contact the country of destination to make sure that you are following their protocol regarding these forms.
These permission letters are not legally required by the Government of Canada. However, some other countries may refuse to allow your child to enter if the permission is not provided in line with their rules and requirements.