As an international student, studying full-time and having a valid study permit, your immediate dependents spouse can apply for an open work permit. Your spouse/partner will not require a job offer to apply, and his/her permit will be valid for the same period as your study permit. Details can be checked at Help your spouse or dependent work in Canada.
Your dependent children can also apply for an open work permit/Study work permit for studying in school in Canada.
Your dependents can apply for a work permit before or after they arrive in Canada. The work permit is usually issued for the same duration of time as your study permit.
In most cases, Canadian visa offices outside of Canada process dependent work permit applications at the same time as study permit applications.
Most dependents come to Canada as visitors first and apply for a work permit after they are in Canada. If your dependents do not require a TRV (Temporary Resident Visa), they can apply for a work permit at the border or airport when they enter Canada.