Christians who specialize in evangelism are often known as evangelists, whether they are in their home communities or living as missionaries in the field, although some Christian traditions refer to such people as missionaries in either case. Some Christian traditions consider evangelists to be in a leadership position; they may be found preaching to large meetings or in governance roles.
Christian groups who encourage evangelism are sometimes known as evangelistic or evangelist.
The word evangelist comes from the Koine Greek word εὐαγγέλιον (transliterated as euangelion) via Latinised evangelium as used in the canonical titles of the Four Gospels, authored by (or attributed to) Matthew, Mark, Luke, and John (also known as the Four Evangelists). The Greek word εὐαγγέλιον originally meant a reward given to the messenger for good news (εὔ = "good", ἀγγέλλω = "I bring a message"; the word "angel" comes from the same root) and later "good news" itself.
The verb form of euangelion, (translated as "evangelism"), occurs rarely in older Greek literature outside the New Testament, making its meaning more difficult to ascertain. Parallel texts of the Gospels of Luke and Mark reveal a synonymous relationship between the verb euangelizo (εὑαγγελίζω) and a Greek verb kerusso (κηρύσσω), which means "to proclaim".
Evangelism can take many forms, such as preaching, distribution of bibles or tracts, newspapers and magazines, by the media, witness, street evangelism. 
The child evangelism movement is a Christian evangelism movement that originated in the 20th century. It focuses on the 4/14 Window which centers on evangelizing children between the ages of 4 and 14 years old.
Beginning in the 1970s, a group of Christian athletes known as The Power Team spawned an entire genre of Christian entertainment based on strong-man exploits mixed with a Christian message and usually accompanied by an opportunity to respond with a prayer for salvation.
New opportunities for evangelization have been provided in recent decades by increased travel opportunities and by instant communications over the internet.
In 1960, more than half of the Protestant American missionaries were evangelical.  The American and European missions pentecostals are also numerous, but pentecostalism will especially develop independently, by non-foreign residents, in various regions of the world, notably in Africa, in America from South and Asia. 
The fact that evangelicals do evangelism and speak about their faith in public is often criticized by the media and associated with proselytism.  According to the evangelicals, freedom of religion and freedom of expression allow them to talk about their faith like anything else.  Christian films made by American evangelical production companies are also regularly associated with proselytism. 
According to Sarah-Jane Murray, screenwriting teacher at the US Film and Christian Television Commission United, Christian films are works of art, not proselytism.  For Hubert de Kerangat, communications manager at Saje distribution, distributor of these American Christian films in France, if Christian films are "proselytes", all films are "proselytes", since each film transmits a message, whether the viewer is free to approve or not.