That depends on who you call. With WiFi calling, it is the same as if you were in the US on an ATT cell tower. No charge to call any US numbers but international long distance to call a number in the country you are in.
Award for Community Excellence 2019 Achiever* *The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.