I. The Sources of Morality

1752
In contrast to the object, the intention resides in the acting subject. Because
it lies at the voluntary source of an action and determines it by its end,
intention is an element essential to the moral evaluation of an action. the end
is the first goal of the intention and indicates the purpose pursued in the
action. the intention is a movement of the will toward the end: it is concerned
with the goal of the activity. It aims at the good anticipated from the action
undertaken. Intention is not limited to directing individual actions, but can
guide several actions toward one and the same purpose; it can orient one’s
whole life toward its ultimate end. For example, a service done with the end of
helping one’s neighbor can at the same time be inspired by the love of God as
the ultimate end of all our actions. One and the same action can also be
inspired by several intentions, such as performing a service in order to obtain
a favor or to boast about it.

From The Catechism of the Catholic Church – rosary.team

Original Link: https://www.vatican.va/archive/ENG0015/__P5R.HTM