Which 14 books in the Bible did the Apostle Paul write?
Books the Apostle Paul wrote, also known as the Pauline Epistles, are as follows;

1. Romans,
2. 1. Corinthians
3. 2 Corinthians
4. Galatians
5. Ephesians
6. Philippians
7. Colossians
8. 1 Thessalonians
9. 2. Thessalonians
10. 1 Timothy
11. 2. Timothy,
12. Titus,
13. Philemon,
14. Hebrews

Conversion from Saul to Paul:
Acts 9
9 Meanwhile, Saul still breathed murderous threats against the Lord’s disciples. He went to the high priest ² and asked him for letters to the synagogues in Damascus so that if he found anyone who belonged to the Way, whether men or women, he might take them as prisoners to Jerusalem. As he approached Damascus on his journey, a light from heaven flashed around him. 4 He fell to the ground and heard a voice say to him, “Saul, Saul, why do you persecute me?”
“Who are you, Lord?” Saul asked.
“I am Jesus, whom you are persecuting,” he replied. 6 “Now get up and go into the city, and you will be told what you must do.”
The men traveling with Saul stood there,, speechless. They heard the sound but did not see anyone. Saul got up from the ground but could see nothing when he opened his eyes. So they led him by the hand into Damascus. 9 For three days, he was blind and did not eat or drink anything.
10 In Damascus, there was a disciple named Ananias. The Lord called to him in a vision, “Ananias!”
“Yes, Lord,” he answered.
11 The Lord told him, “Go to the house of Judas on Straight Street and ask for a man from Tarsus named Saul, for he is praying. In a vision, he has seen Ananias come and place his hands on him to restore his sight.”
13 “Lord,” Ananias answered, “I have heard many reports about this man and all the harm he has done to your holy people in Jerusalem. 14 And he has come here with authority from the chief priests to arrest all who call on your name.”
15 But the Lord said to Ananias, “Go! This man is my chosen instrument to proclaim my name to the Gentiles, their kings, and the people of Israel. 16 I will show him how much he must suffer for my name.”
17 Then Ananias went to the house and entered it. Placing his hands on Saul, he said, “Brother Saul, the Lord—Jesus, who appeared to you on the road as you were coming here—has sent me so that you may see again and be filled with the Holy Spirit.” 18 Immediately, something like scales fell from Saul’s eyes, and he could see again. He got up and was baptized at 19, and after taking some food, he regained his strength.
Saul in Damascus and Jerusalem
Saul spent several days with the disciples in Damascus. At once, he began to preach in the synagogues that Jesus was the Son of God. 21 All those who heard him were astonished and asked, “Isn’t he the man who raised havoc in Jerusalem among those who call on this name? And hasn’t he come here to take them as prisoners to the chief priests?” Yet Saul became more powerful and baffled the Jews living in Damascus by proving that Jesus was the Messiah.
After many days had gone by, there was a conspiracy among the Jews to kill him, but Saul learned of their plan. Day and night, they kept a close watch on the city gates to kill him. But his followers took him by night and lowered him in a basket through an opening in the wall.
26 When he came to Jerusalem, he tried to join the disciples, but they were all afraid of him, not believing he was a disciple. 27 But Barnabas took him and brought him to the apostles. He told them how Saul, on his journey, had seen the Lord and that the Lord had spoken to him and how, in Damascus, he had preached fearlessly in the name of Jesus. So Saul stayed with them and moved about freely in Jerusalem, speaking boldly in the name of the Lord. He talked and debated with the Hellenistic Jews, but they tried to kill him. 30 When the believers learned of this, they took him to Caesarea and sent him off to Tarsus.
31 Then, the church throughout Judea, Galilee, and Samaria enjoyed a time of peace and was strengthened. The number of those living in fear of the Lord and encouraged by the Holy Spirit increased.