What is an evangelist?
I will quote from Smith's Bible Dictionary
Evangelist (publisher of glad tidings). In the New Testament the "evangelists" appear on the one hand after the "apostles" and "prophets;" on the other before the "pastors" and "teachers." They probably stood between the two. Acts 21:8; Eph. 4:11. The work of the evangelist is the proclamation of the glad tidings to those who have not known them, rather than the instruction and pastoral care of those who have believed and been baptized. It follows also that the name denotes a work rather than an order. Its use is nearly like our word missionary.