A spouse and unmarried children under 21 may accompany a TN professional in TD status. TD dependants may attend school but are not authorized to work in the United States, and each must qualify for TD in their own right.
TD allows study and residence, never employment
TD status is derivative: it exists only while Marguerite holds TN, and it carries no work authorization. Her partner could not take a job, freelance or run a business, even a Canadian one operated remotely from inside the United States, without an independent status that permits it. Children can enrol in school.
Two details deserve attention before the family relies on TD. First, the relationship must be a legally recognized marriage for a spouse to qualify; a common-law partner is not a spouse for U.S. immigration purposes and would need another route.
Second, a child who turns 21 loses TD eligibility at that point, so a family with a nineteen-year-old should plan that child's own status early, whether as a student or as a professional in their own right. If the partner's own career matters to the move, compare the TD limit with the L-2 and E-2 spouse rules, which do allow employment incident to status. Hypothetical example: Rafael, a Canadian epidemiologist, plans a move with his spouse, who intends to keep consulting online.
Before choosing TD, the household should identify where the spouse will physically perform services and whether an independent work-authorized category is needed. A marriage certificate and each child's passport resolve the family relationship and identity issues; a vague statement that everyone is 'coming along' does not. Sequence the principal's TN evidence first, then prepare the dependant applications to match its requested period.