In which book of the New Testament do we find the account of the Apostle Paul's conversion and subsequent missionary journeys?

The book in the New Testament where we can find the account of Apostle Paul's conversion and subsequent missionary journeys is the Acts of the Apostles. This book, also known as the Book of Acts, was written by Luke, who was a companion of Paul.
In the beginning of the book, it describes the events surrounding Jesus' ascension into heaven and the coming of the Holy Spirit on the day of Pentecost. After this, it focuses on the early Christian community and the spreading of the gospel to different regions.
In Acts chapter 9, we find the story of Paul's dramatic conversion on the road to Damascus. Paul, formerly known as Saul, was a persecutor of Christians. However, during his journey to arrest Christians, he encountered a bright light from heaven and heard the voice of Jesus asking him why he was persecuting Him. This experience led to Paul's conversion, and he became a dedicated follower of Jesus.
Following his conversion, Acts follows Paul's missionary journeys as he travels throughout different regions such as Antioch, Ephesus, Corinth, and Rome. The book provides detailed accounts of Paul's preaching, miracles, and interactions with various individuals and communities.
Overall, the Acts of the Apostles is the book in the New Testament that narrates Apostle Paul's conversion and his subsequent missionary journeys in a comprehensive and understandable way.