What kind of force is the US using to force oil sellers to only accept USD (assuming they only accept USD). Are Canada and Russia and Iran only accept USD for

What kind of force is the US using to force oil sellers to only accept USD (assuming they only accept USD). Are Canada and Russia and Iran only accept USD for their oil sales? https://www.investopedia.com/articles/company-insights/082316/worlds-top-10-oil-exporters.asp https://www.investopedia.com/articles/company-insights/08231...