I am married and have a child under 18 who lives with us and I am not claiming any dependant credits for her. Do I not list her as a dependant?

[jmerlino00]

Do I list my child who is under 18 under dependants if I am married?

[TurboTaxJennifer]

Yes absolutely list her as a dependant. 

You don't need to claim a specific credit or deduction for her. Certain provincial amounts vary depending on if you have a minor dependant. Letting the software know she's your dependant will ensure that provincial amounts (such as the low-income tax reduction or the Climate Action Incentive in some provinces) are calculated properly.