The Pope introduced the Year of Saint Joseph, to celebrate the 150 years of his Patronage over the Universal Church.
Along with the papal apostolic letter, the Major Penitentiary introduced a set of new plenary indulgences, available until December 8, 2021. The Apostolic Penitentiary letter is here (in Latin and Italian).
The details are the following:
Conditions for the plenary indulgence
The plenary indulgence is granted to the faithful under the usual conditions (sacramental confession, Eucharistic Communion, and prayer for the Pope’s intentions) to Christians who, with a spirit detached from any sin, participate in the Year of St. Joseph on these occasions and manners indicated by the Apostolic Penitentiary: