Liturgy of the Word
"It is preferable that the responsorial Psalm be sung, as least as far as the people's response is concerned. Hence the Psalmist, or the cantor of the Psalm, sings the verses of the Psalm from the ambo or another suitable place".(n61).
Ideally the Psalm (which means "song") is to be sung and sung completely. This can take the form of a cantor singing the verses and the people responding by singing the response, or it may take the form of one complete song. Parishes ought to avoid singing the antiphon and then reciting the verses.
Since the Psalm is Sacred Scripture the ideal is that if a cantor is used, then this person sing/recite from the ambo.
This precedes the reading of the Gospel. This is only to be sung and not recited. "Alleluia" is used during Ordinary, Christmas and Easter times; but NOT during Lent. During Lent other acclamations are used.
Also during Feast Days of Easter and Pentecost, the Sequence may be sung, and this would precede the "Alleluia". These are beautiful texts and all consideration needs to be given to using them.
The Creed is to be sung or said...(n 68).
Yes, there is an option to singing the Creed. If it is done, it is begun by the presider, or the cantor and choir.