Currently, I'm reading an autobiography by late Billy Graham, Just As I Am (1997). In his preface of this book, he writes about what it means by evangelist and I like to quote at length here:
"The word evangelist comes from a Greek word meaning ‘one who announces Good News.' Its verb form occurs over fifty times in the Greek New Testament. An evangelist, then, is like a newscaster on television or a journalist writing for a newspaper or magazine – except that the evangelist's mission is to tell the good news of the Gospel (The word gospel actually means ‘Good News').
"In the Bible, an evangelist is a person sent by God to announce the Gospel, the Good News; he or she has a spiritual gift that never been withdrawn from the Church. Methods differ, but the central truth remains: an evangelist is a person who has been called and specially equipped by God to declare the Good News to those who have not yet accepted it, with the goal of challenging them to turn to Christ in repentance and faith and to follow Him in obedience to His will. The evangelist is not called to do everything in the church or in the world that God wants to be done. On the contrary, the calling of the evangelist is very specific.
"Nor is the evangelist free to change the message, any more than a newscaster is free to change the news. The main thrust of our message is centered in Christ and what He has done for us by His death and resurrection, and the need for us to respond by committing our lives to Him. It is the message that Christ came to forgive us and give us new life and hope as we turn to Him."
THINK BIG. START SMALL. GO DEEP.