Matthew 18:19-20 "Again, [amen,] I say to you, if two of you agree on earth about anything for which they are to pray, it shall be granted to them by my heavenly Father. 20 For where two or three are gathered together in my name, there am I in the midst of them.”
Phillippians 4:6 - Have no anxiety at all, but in everything, by prayer and petition, with thanksgiving, make your requests known to God.
2644 The Holy Spirit who teaches the Church and recalls to her all that Jesus said also instructs her in the life of prayer, inspiring new expressions of the same basic forms of prayer: blessing, petition, intercession, thanksgiving, and praise.
2645 Because God blesses the human heart, it can in return bless him who is the source of every blessing.
2646 Forgiveness, the quest for the Kingdom, and every true need are objects of the prayer of petition.
2647 Prayer of intercession consists in asking on behalf of another. It knows no boundaries and extends to one’s enemies.
2648 Every joy and suffering, every event and need can become the matter for thanksgiving which, sharing in that of Christ, should fill one’s whole life: “Give thanks in all circumstances” (1 Thess 5:18).
2649 Prayer of praise is entirely disinterested and rises to God, lauds him, and gives him glory for his own sake, quite beyond what he has done, but simply because HE IS.
From Catechism of the Catholic Church