Can. 349 The Cardinals of the Holy Roman Church constitute a special College, whose prerogative it is to elect the Roman Pontiff in accordance with the norms of a special law. The Cardinals are also available to the Roman Pontiff, either acting collegially, when they are summoned together to deal with questions of major importance, or acting individually, that is, in the offices which they hold in assisting the Roman Pontiff especially in the daily care of the universal Church.
Can. 350 §1. The College of Cardinals is divided into three orders: the episcopal order, to which belong those Cardinals to whom the Roman Pontiff assigns the title of a suburbicarian Church, and eastern-rite Patriarchs who are made members of the College of Cardinals; the presbyteral order, and the diaconal order.
§2. Cardinal priests and Cardinal deacons are each assigned a title or a deaconry in Rome by the Roman Pontiff. [Latin Code of Canon Law 1983]