There are a lot of different documents that come out of the Vatican. How do we know which to pay attention to and which are of greater or lesser importance?
Since I admit I am not up to date on my hierarchy of papal documents, I invite you to visit a webpage called: A Pocket Guide for Different Papal Documents April 1, 2020, by Ramzi Bishtawi who researched it.
Apostolic Constitutions are the most solemn papal document and are typically addressed to the public. This form of legislation is important in dealing with doctrinal and disciplinary matters of a local church or the Church as a whole.
Encyclicals are letters of pastoral or theological content, meant to be read by all of the faithful. These letters are typically longer reflections, on topics of importance to the pope. While an encyclical does not hold the weight of a constitution, it nevertheless holds high papal authority for a given issue.
Apostolic Exhortations are addresses emphatically urging the faithful to consider a particular spiritual matter or activity, of importance to the Pontiff. Despite the similarities, apostolic exhortations carry less authority than encyclicals, and are not considered legislative.
Apostolic Letters are written by the Pontiff in response to a specific need or addressed to a specific group of people. These letters are pastoral in nature, but not legislative.
Motu Proprio, which translates to “by one’s own initiative,” is a legislative document dealing with specific issues relevant to the Church in a given time in history. A motu proprio is issued by the pope himself and can be on any topic.
Papal Bulls are official declarations or announcements issued by the pope. A papal bull was used by St. John Paul II to announce the Jubilee Year of 2000.
Papal Rescripts are usually written in response to a petition placed before the Roman Curia, the administrative institutions of the Holy See, or the pope himself. These papal rescripts are meant to make new laws or modify existing ones.
Decretal Letters are letters of a pope containing a decretum, a pontifical decision. Canonizations and dogmatic definitions, for example, are often decreed in the form of a decretal letter.
Breva, or Apostolic Briefs, are lowest on the hierarchy of papal messages, and they deal with matters of relatively minor importance.