In the Catholic Church, applause is generally not a common form of expression during liturgical celebrations. Mass and the other sacraments are sacred rites and are meant to be approached with reverence and solemnity.
In some situations, however, applause may be appropriate, such as after the ordination of a new priest or bishop. In these cases, the presiding priest or bishop may indicate that it is appropriate to offer applause.
It is important to remember, however, that the focus of Mass and other liturgical celebrations is not on the congregation’s response or reaction but on the worship of God. Mass is not a time of entertainment. Applause is for human efforts, while worship is for God. Therefore, any expressions of applause or other forms of response should be done in a way that is respectful and does not detract from the overall solemnity of the celebration.