He has used a prayer attributed to a Spanish cardinal who promoted the Litany of Humility.
At the end of his daily Mass, Pope Francis has led the faithful in making a Spiritual Communion.
He has recited this prayer:
At Thy feet, O my Jesus, I prostrate myself and I offer Thee repentance of my contrite heart, which is humbled in its nothingness and in Thy holy presence. I adore Thee in the Sacrament of Thy love, the ineffable Eucharist. I desire to receive Thee into the poor dwelling that my heart offers Thee. While waiting for the happiness of sacramental communion, I wish to possess Thee in spirit. Come to me, O my Jesus, since I, for my part, am coming to Thee! May Thy love embrace my whole being in life and in death. I believe in Thee, I hope in Thee, I love Thee. Amen.
This prayer is attributed to Servant of God Rafael Merry del Val. This cardinal is known for having promoted the Litany of Humility.
The practice of Spiritual Communion was noted by St. John Paul II in his last encyclical, Ecclesia de Eucharistia.
The Eucharist thus appears as the culmination of all the sacraments in perfecting our communion with God the Father by identification with his only-begotten Son through the working of the Holy Spirit. With discerning faith a distinguished writer of the Byzantine tradition voiced this truth: in the Eucharist “unlike any other sacrament, the mystery [of communion] is so perfect that it brings us to the heights of every good thing: here is the ultimate goal of every human desire, because here we attain God and God joins himself to us in the most perfect union.” Precisely for this reason it is good to cultivate in our hearts a constant desire for the sacrament of the Eucharist. This was the origin of the practice of “spiritual communion,” which has happily been established in the Church for centuries and recommended by saints who were masters of the spiritual life. Saint Teresa of Jesus wrote: “When you do not receive communion and you do not attend Mass, you can make a spiritual communion, which is a most beneficial practice; by it the love of God will be greatly impressed on you.”
There are various established prayers for making a Spiritual Communion, or you can make the request to Jesus using your own words.