If you are submitting in person (as a Passport Canada location) you would not be able to get a passport for your granddaughter. The only persons permitted to submit a child who is under 16 years of age are;
One of the child’s parents
Custodial parent in the case of separation or divorce or
Legal guardian (proof of legal guardianship must be provided)
IIf you are sending by mail/ courier you can apply for both your daughter and granddaughter in the same envelope.