The Morning Offering is an aspect of the League of the Sacred Heart of Jesus' "Apostleship of Prayer," born in 1844 in a Jesuit seminary in Vals, France. The seminarians were destined to evangelize in Indian and American missions and, anxious to get on with their work, were reminded by their spiritual Father, Fr. Francois Xavier Gautrelet, that salvation is supernatural and that they can also get on with their apostleship through prayer and by offering up their sufferings, joining them with Christ's: Colossians 1:23-24: "I Paul am made a minister; who now rejoice in my sufferings for you, and fill up that which is behind of the afflictions of Christ in my flesh for his body's sake, which is the church."
Later, another Jesuit, Jesuit Father Ramiere, began to publish the "Messenger of the Sacred Heart" to spread devotion to the Sacred Heart of Jesus. This helped to spread the "Morning Offering Prayer," encouraging the faithful to begin each day by offering that day and its sufferings to the Lord for the good of the Church.
At first, the "Morning Offering" included offering up "prayers, works and suffering," but a nun urged Pope Pius XII to include the concept of joy. The Holy Father agreed, and so some forms of the Morning offering now include offering up "our prayers, works, joys and suffering."
The Offering is meant to be prayed first thing in the morning, consecrating the day to the Lord and preparing one to focus all on Jesus and give to Him all that one does during the day. There are a few variations of the Morning Offering, some offering our oblations to Jesus in imitation of Mary's Immaculate Heart. Here is a common form:
Lord Jesus Christ, in union with that divine intention wherewith on earth Thou didst offer to God Thy praises through Thy Most Sacred Heart, and dost now offer them in the Sacrament of the Eucharist everywhere on earth even to the end of time, I most gladly offer Thee throughout this entire day, all my thoughts and intentions, all my affections and desires, all my words and deeds, in imitation of the most sacred Heart of the blessed and ever Virgin Mary Immaculate. Amen.
O Jesus, through the Immaculate Heart of Mary, (here kiss your brown scapular) and in union with the Holy Sacrifice of the Mass being offered throughout the world, I offer You all my prayers, works, joys and sufferings of this day in reparation for the offenses committed against the Immaculate Heart of Mary, for my sins and the sins of the whole world.
Now, throughout the day, offer up your hardships and sacrifices to Jesus, uniting them with His sufferings and merits so that our works gain the merit they can never have apart from Him. It is especially beneficial to offer them to Mary to give to Jesus so that her intercession as Queen Mother of Israel renders them more pleasing.
The Morning Offering can be renewed throughout the day with simple short prayers (called "ejaculations" or "aspirations"), for ex., "All for Thee, Jesus!"