The Catholic Church has always given an important place to the Blessed Virgin. Already in 1964, through Pope Paul VI, the Church declared the Blessed Virgin Mary Mother of the Church, noting that "the entire Christian people has always and increasingly honored the Mother of God with this most sweet name." A more and more important place was given to this title, by different means: votive mass, an option to add the invocation of this title in the Litanies...
Since March 5, 2018, by a decision of Pope Francis, each year on Pentecost Monday, the memory of Mary, Mother of the Church has been made obligatory for the entire Church of the Roman Rite. Here are some short excerpts from the Decree on the celebration of the Blessed Virgin Mary, Mother of the Church in the General Roman Calendar:
"The joyous veneration given to the Mother of God by the contemporary Church, in light of reflection on the mystery of Christ and on his nature, cannot ignore the figure of a woman (cf. Gal 4:4), the Virgin Mary, who is both the Mother of Christ and Mother of the Church.
[...] Pope Francis has decreed that the Memorial of the Blessed Virgin Mary, Mother of the Church, should be inscribed in the Roman Calendar on the Monday after Pentecost and be now celebrated every year.
This celebration will help us to remember that growth in the Christian life must be anchored to the Mystery of the Cross, to the oblation of Christ in the Eucharistic Banquet and to the Mother of the Redeemer and Mother of the Redeemed, the Virgin who makes her offering to God."
Excerpt from the Decree on the celebration of the Blessed Virgin Mary Mother of the Church in th General Roman Calendar - issued by the Congregation of Divine Worship and the Discipline of the Sacraments, on February 11, 2018