Apostolic letters are formal documents written by the Pope or other church leaders to address specific issues within the Catholic Church or to provide guidance to the faithful. These letters often discuss theological matters, moral teachings, or social issues, and they aim to instruct and inspire believers. These letters can take various forms, including encyclicals, exhortations, and motu proprios. Each type serves a different purpose, but all are intended to communicate important messages to the Christian community. Apostolic letters are significant in shaping church doctrine and practice.