Prayer is communicating with God.
Prayer can be formal or informal, verbal or nonverbal, active or contemplative. Just as we talk and share with our best friends what is happening in our lives, so we talk and share with God. Just as we listen to our friends, so we listen to God. We communicate with God using words and songs, in imagination and silence, and ritually or spontaneously. We can pray in church, our gardens, our cars, or while in the shower. We can also pray lying in bed, as the first thing we do when we awake, and as the last thing we do as we drift off to sleep.
One of the characteristics of prayer we as Catholics believe is that with the right intention every moment of the day—all our hopes, works, joys, and sufferings—can become our prayer. Prayer can be vocal (spoken out loud), meditative (thinking or reflecting about God) or contemplative (resting quietly in God's presence).
Prayer creates and maintains a vital and personal relationship with the living and true God. Prayer is a solemn request for help or expression of thanks addressed to God. In John 4:10 Jesus describes prayer as the gift of God to the woman at the well. Communal prayers include not only the Mass but also the Rosary, devotional prayers such as novenas and litanies and classroom prayers.
Traditional prayers include the Sign of the Cross, the Hail Mary, the Lord’s Prayer and mealtime and bedtime blessings. At Mass when the presider invites each one of us to “Lift up your hearts.” and our response is “We lift them up to the Lord,” we are praying and lifting our hearts to God. More Prayers... Source: How Catholics Pray
The Bible contains many scriptures about prayer. Jesus prayed often and asked others to pray with him. He would slip away to have moments of prayer with his Father. In the Bible, Genesis 4:26 first mentions that "men began to call on the name of the Lord," and Revelation 22:20 closes the Bible with a prayer. In 1 Thess 5:17, God commands us to “pray without ceasing.”
Prayer is a covenant relationship with God expressed in words and gestures. According to Scripture, it is the heart that prays. If our heart is far from God, the words of prayer are in vain. CCC, no. 2562-2564 "For me, prayer is a surge of the heart; it is a simple look turned toward heaven, it is a cry of recognition and of love, embracing both trial and joy." CCC, no. 2558, citing St. Therese of Lisieux, Manuscrits Autobiographiques, C 25rr
In the New Covenant, prayer is the living relationship of the children of God with the Trinity - Father, Son Jesus Christ and the Holy Spirit. The life of prayer is the habit of being in the presence of the triune God and in communion with him. Through Baptism we have already been reunited with Jesus Christ. CCC, no. 2565
Descriptions of prayer are abundant throughout Christian history.
"True prayer," wrote St. Augustine, "is nothing but love." Prayer should arise from the heart. "Prayer," said St. John Vianney, "is the inner bath of love into which the soul plunges itself."
"Everyone of us needs half an hour of prayer each day," remarked St. Francis de Sales, "except when we are busy—then we need an hour."
Definitions of prayer are important, but insufficient. There is a huge difference between knowing about prayer and praying. On this issue, the Rule of St. Benedict is clear, "If a man wants to pray, let him go and pray."
St. John Damascene gave a classic definition of prayer: "Prayer is the raising of one's mind and heart to God or the requesting of good things from God" (CCC, no. 2559, citing St. John Damascene, De Fide Orth. 3, 24).
Prayer is Christian "insofar as it is communion with Christ" (CCC, no. 2565), and a "covenant relationship between God and man in Christ" (CCC, no. 2564).
Adoration, a contemplative prayer, is the first attitude of man acknowledging that he is a creature before his Creator. It exalts the greatness of the Lord who made us and the almighty power of the Savior who sets us free from evil. Adoration is homage of the spirit to the "King of Glory," respectful silence in the presence of the "ever greater" God. Adoration of the thrice-holy and sovereign God of love blends with humility and gives assurance to our supplications. Catechism of the Catholic Church, no. 2628
One of the most powerful things you can do for a friend or loved one or someone who is hurting and in need of God's grace is to pray for them. The first public words of Pope Francis were to ask others to pray for him. There are many miraculous stories of the healing power of prayer. The power of prayer is the power of God, who hears and answers prayer.
"The Lord God Almighty can do all things; there is nothing impossible for Him " Luke1:37