A U.S. citizen who is a resident of Canada does not pay U.S. tax on Social Security benefits. I don't know whether you have to pay Canadian tax on the benefits, but I would assume so.
In TurboTax for your U.S. tax return you enter the Social Security benefits from your Form SSA-1099 normally, the same as you would if you were living in the United States. After you enter the SSA-1099 you will come to a screen that asks whether you are a U.S. citizen living in one of the countries where your Social Security benefits are exempt from U.S. tax. If you answer Yes the benefits will be excluded from the taxable income on your U.S. tax return. The wording of the question might change for 2025 because it seems to have caused some confusion for 2024, but TurboTax will have a way to handle the exemption. Read the screens carefully.
