Hello this is an easy question since the Bible characters named John, Mark, Luke and other are not real people and do not live outside of the Bible. The concept of using visions as communication is not for nothing because they display divine origin and something that humans experience. Another thing is that they are private and direct, this is also a human experience. The details of Jesus Missionary and where he preached, and places he traveled to make up the first four gospels of the New Testament.
The remainder of the other books of the New Testament are the works of the followers of Jesus Christ. This is used to create the Christians religion which emphasis faith and express how it was preached in other lands by the followers of Jesus Christ. It is also used to display the faith as examples of devout Christians, they also served as eyewitnesses of many of the events that Jesus gave or did. So, what is the information in the writings of the New Testament? The examples of the preaching of the life works of Jesus Christ and his miraculous resurrection from the dead. How the disciples and followers of Jesus empowered to keep going as the Good News spread to all the world. How the Holy Spirit acted as an influencer on newly founded faith, how stories and prophecy was centered on people that either displayed faith or rejected it. What passage in the Bible tells us what the future would look like for those that truly believed in God and the words of the Holy Bible?
Modern English Version (MEV)
The Outpouring of the Spirit
28 And it will be that, afterwards,
I will pour out My Spirit on all flesh;
then your sons and your daughters will prophesy,
your old men will dream dreams,
and your young men will see visions.
29 Even on the menservants and maidservants
in those days I will pour out My Spirit.