Catechism of the Catholic Church
1669 Sacramentals derive from the baptismal priesthood: every baptized person is called to be a “blessing,” and to bless.174 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).175
174 Cf.
Gen 12:2;
Lk 6:28;
Rom 12:14;
1 Pet 3:9.
175 Cf.
SC 79; CIC, can. 1168;
De Ben 16,18.
1670 Sacramentals do not confer the grace of the Holy Spirit in the way that the sacraments do, but by the Church’s prayer, they prepare us to receive grace and dispose us to cooperate with it. "For well-disposed members of the faithful, the liturgy of the sacraments and sacramentals sanctifies almost every event of their lives with the divine grace which flows from the Paschal mystery of the Passion, Death, and Resurrection of Christ. From this source all sacraments and sacramentals draw their power. There is scarcely any proper use of material things which cannot be thus directed toward the sanctification of men and the praise of God."176
176
SC 61
Note: SC = Constitution Sacrosanctum concilium Modern Catholic Dictionary:
BLESSING. As found in Scripture, it means praise, the desire that good fortune go with a person or thing, dedication of a person or thing to God’s service and a gift. In liturgical language a blessing is a ritual ceremony by which an authorized cleric in major orders sanctifies persons or things to divine service, or invokes divine favor on what he blesses. The Church’s ritual provides for over two hundred such blessings, some of which are reserved to bishops or members of certain religious institutes.
**ACTUAL GRACE. **Temporary supernatural intervention by God to enlighten the mind or strengthen the will to perform supernatural actions that lead to heaven. Actual grace is therefore a transient divine assistance to enable man to obtain, retain, or grow in supernatural grace and the life of God.
I believe the distinction between Papal, episcopal, presbyter, deacon, and laity is this, regarding the giving of blessings: The priest may give all blessings except those reserved to the bishops and Pope. Parents may bless their children, and deacons can give blessings as designated in church law. (Eastern Catholic deacons cannot give blessings per law.)
See this answer:
forums.catholic-questions.org/showthread.php?t=122933