The Supreme Pontiff usually conducts the affairs of the universal Church through the Roman Curia which performs its function in his name and by his authority for the good and service of the churches. The Roman Curia consists of the Secretariat of State or the Papal Secretariat, the Council for the Public Affairs of the Church, congregations, tribunals, and other institutes; the constitution and competence of all these are defined in special law.
Source: Code of Canon Law (Vatican.va)