Canadians are exempt from many types of United States visas. They are exempt from requiring a TN visa.
A US visa is issued by US consulates or embassies and is really an endorsement made upon a foreign passport permitting the passport holder to present himself or herself for entry into the United States. A visa does not guarantee entry as that decision is up to the US border official inspecting the foreign national.
Canadians normally request TN status at the border from US Customs and Border Protection or from inside the United States from US Citizenship and Immigration Services. The procedures and costs differ between the two agencies. If approved, he or she would obtain an electronic or paper Form I-94 as proof of TN status instead of a visa.
Spouses and children under 21 years of age of the TN status holder are allowed to obtain “TD” status or a “TD” visa. If the spouse and children are Canadian then usually everyone can apply for TN and TD status at the same time. If the spouse and children are not Canadian, they may apply at a US consulate for a TD visa once the Canadian spouse or parent has TN status.
TD status or a TD visa allows the spouse or child to live with you in Florida or with you anywhere else in the United States, but TD status does not allow a spouse or child to work legally. The spouse or child would need a different legal reason to obtain employment authorization.
Mexican citizens are also eligible for TN or TD visas, but US law treats Mexican citizens differently than Canadians so the information written in this answer only applies to Canadians as of the date of this writing.
If you have any questions regarding immigration, please feel free to call me, immigration attorney Shawn Mesa at (813) 679-5780.
Disclaimer: This information is provided as a public service and not intended to establish an attorney-client relationship. Any reliance on this information is taken at your own risk.