From the very beginning, the Church has sent out people on a mission to proclaim the Gospel, the Word of God, all over the world. Jesus himself commissioned all the baptised faithful to preach the Gospel to anyone who wants to listen (Mk. 16:15). Christians can do so primarily by the way they live their lives.
Pope John Paul II called for a New Evangelisation aimed at all people who do not yet know the Gospel of Jesus, or who no longer have a living faith.