Prayer is a communication to God. Many believe their prayers are answered and evidence of it is primarily reported in the Old and New Testament. Later miracles and graces have been reported by the Church and by common people. Prayer is done by those who trust the power of word and thought. Jesus taught people to say the Lord's Prayer.
Prayer can be spoken, silent (no talking), or in a song. It can be used to praise God or to ask for something including help and forgiveness. Prayers can be said over and over again as in a Rosary or just once. The Rosary includes Lord's Prayer and several others.