Is the Creed a prayer? (Catholic mass)
The short answer is no.
While the creed is said at Mass, at the beginning of the rosary and on other occasions, it remains simply a code of Catholic beliefs.
I believe. A creed or code of beliefs; also applied to any one article of faith. (Etym. Latin credo, I believe.)
St. Thomas Aquinas explains the three conditions that make up a prayer and the creed does not constitute a single condition at all.
Three conditions are requisite for prayer. First, that the person who prays should approach God Whom he prays: this is signified in the word "prayer," because prayer is "the raising up of one's mind to God." The second is that there should be a petition, and this is signified in the word "intercession." On this case sometimes one asks for something definite, and then some say it is "intercession" properly so called, or we may ask for some thing indefinitely, for instance to be helped by God, or we may simply indicate a fact, as in John 11:3, "Behold, he whom Thou lovest is sick," and then they call it "insinuation." The third condition is the reason for impetrating what we ask for: and this either on the part of God, or on the part of the person who asks. The reason of impetration on the part of God is His sanctity, on account of which we ask to be heard, according to Daniel 9:17-18, "For Thy own sake, incline, O God, Thy ear"; and to this pertains "supplication" [obsecratio] which means a pleading through sacred things, as when we say, "Through Thy nativity, deliver us, O Lord." The reason for impetration on the part of the person who asks is "thanksgiving"; since "through giving thanks for benefits received we merit to receive yet greater benefits," as we say in the collect [Ember Friday in September and Postcommunion of the common of a Confessor Bishop]. Hence a gloss on 1 Timothy 2:1 says that "in the Mass, the consecration is preceded by supplication," in which certain sacred things are called to mind; that "prayers are in the consecration itself," in which especially the mind should be raised up to God; and that "intercessions are in the petitions that follow, and thanksgivings at the end."
We may notice these four things in several of the Church's collects. Thus in the collect of Trinity Sunday the words, "Almighty eternal God" belong to the offering up of prayer to God; the words, "Who hast given to Thy servants," etc. belong to thanksgiving; the words, "grant, we beseech Thee," belong to intercession; and the words at the end, "Through Our Lord," etc. belong to supplication.
In the "Conferences of the Fathers" (ix, cap. 11, seqq.) we read: "Supplication is bewailing one's sins; prayer is vowing something to God; intercession is praying for others; thanksgiving is offered by the mind to God in ineffable ecstasy" [adoration]. The first explanation, however, is the better. - Article 17. Whether the parts of prayer are fittingly described as supplications, prayers, intercessions, and thanksgivings?
Elsewhere St. Thomas in question 84.2 of his Summa, speaks more exactly about adoration as follows:
Adoration is directed to the reverence of the person adored. Now it is evident from what we have said (God). Hence the adoration whereby we adore God is an act of religion.
There are four basic forms of prayer and the creed is not one of them:
Prayer of Blessing and Adoration
In this prayer we express praise and honor to God. We praise God for giving us life, for the wonder and beauty of our world, and for all the many blessings we enjoy. We open ourselves up to praise God for all the wonders of creation. This form of prayer encourages bodily expression, such as standing with arms raised or dancing.
Prayer of Petition
This is probably the most familiar prayer form of prayer. We are often taught to ask God for the things we need, but asking and praying for them are not necessarily the same. When we pray our petitions, we are asking God, who loves us very much, for something that we believe is good—for ourselves or for others. By using this form of prayer we are mindful of the needs of others as well as of our own needs. We are aware that God wants us to bring our problems and worries to prayer knowing that he will always hear and answer those prayers. God may answer our prayers in a different way and in a different timeframe than we are seeking but God will always give us what we need.
Prayers of petition serve to remind us that God expects us to care for one another and for all his creation. We can pray about the ordinary experiences of life— for people who are sick, for someone who needs a job, for help in our school work, for a safe trip. We pray for peace in our families and in our world. We can also express our sorrow and contrition to God in our prayer.
Prayer of Intercession
This form of prayer is prayer on behalf of others. This form of prayer can be a source of blessing upon others, the Church, and our world. Because we know that Our Lady and the saints intercede for us before God, the Church encourages us to pray to them for their intercession. Such prayer can bring us great strength and courage and also great peace of mind and heart.
Prayer of Thanksgiving
This form of prayer helps us to be grateful for God's many blessings, spiritual and temporal, and helps us to recognize and appreciate all the good things God gives to us. Reserving some time to praise and thank God for his gifts—the gift of life; the gift of our families and friends; the gift of food, clothing, and shelter; and the numerous other gifts we often take for granted—helps us to form a true spirit of gratitude. - Basic Forms of Prayer