When shipping from the US to Canada, avoiding duties is possible if the value of your products is under $20 CAD (~$14 USD). If the parcel exceeds the limit, it's subject to taxes, which is usually handled by the carrier. Advice: Consider self-accounting
to save on regulatory fees when your ship to Canada's costs need controlling.
Other than that, how much orders weigh, volume, and the required speed of delivery determine how much international shipping to Canada would cost your business. Depending on specifics, there are usually many affordable options for your package from different couriers.