The Catechism of the Catholic Church teaches, “The Eucharist is a sacrifice of thanksgiving to the Father, a blessing by which the Church expresses her gratitude to God for all his benefits, for all that he has accomplished through creation, redemption and sanctification” (CCC 1360).  

The ordinary ministers of Holy Communion are ordained bishops, presbyters, and deacons. 336.02 When Extraordinary Ministers are Permitted. Extraordinary ministers of Holy Communion may distribute communion only when the ordinary ministers are insufficient in number, unavailable, or impeded.

Before receiving a mandate from the Diocesan Bishop, 
prospective extraordinary ministers are to receive the necessary formation for their function. 
The formation is to include instruction on: 
 (a) the mystery of the Eucharist and the Real Presence; 
 (b) the theology and spirituality of Holy Communion; 
 (c) the role of an extraordinary minister; and 
 (d) all practical directions for reverently caring for the Blessed Sacrament and fulfilling their 
liturgical function.

 Extraordinary ministers of Holy Communion: 
 (a) must be fully initiated Catholics; 
 (b) must be at least 16 years of age; 
 (c) may not be subject to any imposed or declared ecclesiastical censure; 
 (d) must manifest a devotion to the Blessed Sacrament; and 
 (e) must living a life of faith in accord with the function to be undertaken. 

The people listed below are recommended to be commissioned for a three-year period as Extraordinary Ministers of Holy Communion at mass and/or for Visitation of the Sick. They have received sufficient preparation for this ministry. After their commissioning, these ministers will distribute Holy Communion at Mass or bring Communion to the sick as indicated below. 

Pastors are to request a mandate for 
extraordinary ministers who are to serve in his Parish in writing from the Diocesan Bishop. 
 (a) The request is to list the names of those to receive the mandate and is to certify that they 
have been properly formed and meet the requirements in universal and particular law. 
 (b) Mandates to serve as an extraordinary minister are granted for a period of three (3) years, 
unless renewed upon their expiration. 
 (c) After having been duly instructed, and after having received their mandate from the 
Diocesan Bishop, extraordinary ministers of Holy Communion are to receive a blessing in 
a Parish ceremony before beginning their ministry. 

USCCB Notes  Letter for Mandate  Order of Commissioning in Mass  Order of Commissioning Outside Mass