Every person is called to the great commission, the minsitry of salvation, which is to share Christ. Evangelism is more than tha
Matthew 28:19–20
19 Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:
20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen.
Every person has a gift that the Holy Spirit gives you, and this gift will connect directly to your personality. If your called to be an evangelist, which is to say a person who seeks to convert others to the Christian faith, especially by public preaching. You will know this is your specific calling if your natural gifts and area of comfort is public speaking.
This is not to say, that a person who never wanted to speak publicly is not called to be a pastor, preacher, evangelist etc. In most cases those that are in these offices did not have a nature draw towards public speaking.
My point is, the drive to be in front of groups in teaching, regardless of your inclination, is a call from the Holy Spirit in His service. If you never wanted to be in public but are feeling the draw to do so, thats evidence of the call,
If you've always been comfortable in front of people and feel the draw in ministry that can also be evidence of this call. The way to narrow this down is through the evidence of the accompanying gift the Holy Spirit has given you.
An example would be the hunger to learn more and more about scripture and the enthusiasm you experience when sharing the word, this disposition should be embolden with the gift the Holy Spirit if your called to be an evangelist.
There are offices of ministry and gifts that support those offices.
Romans 12:4–7 - The Offices
4 For as we have many members in one body, and all members have not the same office:
5 So we, being many, are one body in Christ, and every one members one of another.
6 Having then gifts differing according to the grace that is given to us, whether prophecy, let us prophesy according to the proportion of faith;
7 Or ministry, let us wait on our ministering: or he that teacheth, on teaching;
8 Or he that exhorteth, on exhortation: he that giveth, let him do it with simplicity; he that ruleth, with diligence; he that sheweth mercy, with cheerfulness.
1 Corinthians 12:4–14 - The Gifts
4 Now there are diversities of gifts, but the same Spirit.
5 And there are differences of administrations, but the same Lord.
6 And there are diversities of operations, but it is the same God which worketh all in all.
7 But the manifestation of the Spirit is given to every man to profit withal.
8 For to one is given by the Spirit the word of wisdom; to another the word of knowledge by the same Spirit;
9 To another faith by the same Spirit; to another the gifts of healing by the same Spirit;
10 To another the working of miracles; to another prophecy; to another discerning of spirits; to another divers kinds of tongues; to another the interpretation of tongues:
11 But all these worketh that one and the selfsame Spirit, dividing to every man severally as he will.
12 For as the body is one, and hath many members, and all the members of that one body, being many, are one body: so also is Christ.
13 For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.
14 For the body is not one member, but many.