Correct. It's a tax treaty form and there is no visa application required if you are only working from Canada. Many companies don't know about it and think that paying people out of the US will be a big headache, but they literally only have to fill out the one form and then not take off tax. It basically says "we both are confirming that the Canadian works in a place with a tax treaty with the US and will be paying income tax there so no tax needs to be with-held". I worked somewhere that knew this first, and then worked at 2 more places where I had to educate the payroll department about it! (They tried to send me forms that clearly said "I am a US citizen" and I was like "hellooo I can't sign this, that would be fraud".