Upon their arrival in Canada, and before they can carry out their duties as heads of mission, new ambassadors, as well as new high commissioners of countries for which Her Majesty Queen Elizabeth II is not Head of State, must be officially welcomed by the governor general of Canada. High commissioners representing countries for which The Queen is the Head of State are formally introduced to the prime minister of Canada.
Credentials are the official documents by which new heads of diplomatic missions are presented by their Head of State as their official representative. Formal presentation ceremonies take place at the official residences of the governor general, either at Rideau Hall in Ottawa or at the Citadelle of Québec. Currently, there are more than 180 heads of diplomatic missions accredited to Canada.