The New Testament book of Acts describes Paul’s conversion on the road to Damascus.
Acts presents the event three times: in Acts 9 as narrative, and in Acts 22 and Acts 26 as Paul’s speeches. Before the event, Paul—then called Saul—is portrayed as opposing the early Christian movement. While traveling to Damascus, he experiences a heavenly vision of Jesus, loses his sight temporarily, and later receives baptism.
The account identifies Ananias as the disciple in Damascus who visits Saul, restores his sight, and helps him begin his new mission. Acts then follows Paul’s work as a major missionary and speaker in the expansion of Christianity beyond Judea.
The Pauline letters also refer to Paul’s encounter with Christ, but they do not reproduce the extended road narrative found in Acts. That is why Acts is the most specific answer to this question.