Catechism of the Catholic Church
a, b, d, and e. Para. 1669: Sacramentals derive from the baptismal priesthood: every baptized person is called to be a "blessing," and to bless (Cf. Gen 12:2; Lk 6:28; Rom 12:14; 1 Pet 3:9). Hence lay people may preside at certain blessings; the more a blessing concerns ecclesial and sacramental life, the more is its administration reserved to the ordained ministry [bishops, priests, or deacons](Cf. SC 79; CIC, can. 1168; De Ben 16, 18).
Para. 1671: Among sacramentals blessings (of persons, meals, objects, and places) come first. Every blessing praises God and prays for his gifts. In Christ, Christians are blessed by God the Father "with every spiritual blessing" (Eph 1:3). This is why the Church imparts blessings by invoking the name of Jesus, usually while making the holy sign of the cross of Christ.
Para. 1672: Certain blessings have a lasting importance because they consecrate persons to God, or reserve objects and places for liturgical use. Among those blessings which are intended for persons—not to be confused with sacramental ordination—are the blessing of the abbot or abbess of a monastery, the consecration of virgins and widows, the rite of religious profession and the blessing of certain ministries of the Church (readers, acolytes, catechists, etc.). The dedication or blessing of a church or an altar, the blessing of holy oils, vessels, and vestments, bells, etc., can be mentioned as examples of blessings that concern objects.