Beginning Friday, Canadians over the age of 14 who will be in the United States for 30 days or longer will have to register with U.S. Citizenship and Immigration Services. The Trump administration says it's just enforcing laws that essentially have been on the books for decades.
This is probably “newly” enforced but if they fly they should automatically receive an I-94 at immigration and I’d they enter by car they need to specify to the agent that that are staying more than 30 days or travelling more than ~50 miles from the border (I’m not sure about the distance) and apply for an I-94 at the border crossing, it’s the same rule for Mexicans, the difference is that the South border has checkpoints where you can’t cross with a visa without an I-94
Many who fly would have already received the required I-94 form, and they don’t have to register if they’ve previously submitted it. Most driving to the U.S. aren’t handed an I-94
This is probably “newly” enforced but if they fly they should automatically receive an I-94 at immigration and I’d they enter by car they need to specify to the agent that that are staying more than 30 days or travelling more than ~50 miles from the border (I’m not sure about the distance) and apply for an I-94 at the border crossing, it’s the same rule for Mexicans, the difference is that the South border has checkpoints where you can’t cross with a visa without an I-94