From the Catechism of the Catholic Church:
The Effects of Confirmation
1302 It is evident from its celebration that the effect of the sacrament of Confirmation is the special outpouring of the Holy Spirit as once granted to the apostles on the day of Pentecost. (731)
1303 From this fact, Confirmation brings an increase and deepening of baptismal grace: (1262–1274; 2044)
— it roots us more deeply in the divine filiation which makes us cry, “Abba! Father!”;
[Source: Catholic Church. (2000). Catechism of the Catholic Church (2nd Ed., p. 330). Washington, DC: United States Catholic Conference.]