In the Canadian system of government, the Queen, represented by the governor general, embodies the highest authority.
the Queen is sovereign. The Governor General exercises the Queen's powers as her representative in Canada. The role of the Queen and her representative in Canadian government is essentially ceremonial, except for the Governor General's responsibility to ensure adherence by the Prime Minister to the confidence convention of responsible government.
Head of state or chief of state is the generic term for the individual or collective office that serves as the chief public representative of a monarchic or republican nation-state, federation, commonwealth or any other political state. His or her role generally includes personifying the continuity and legitimacy of the state and exercising the political powers, functions and duties granted the head of state in the country's constitution.