Question: "Who divided the Bible into chapters and verses? Why and when was it done?"
Answer: When the books of the Bible were originally written, they did not contain chapter or verse references. The Bible was divided into chapters and verses to help us find Scriptures more quickly and easily. It is much easier to find "John chapter 3, verse 16" than it is to find "for God so loved the world..." In a few places, chapter breaks are poorly placed and as a result divide content that should flow together. Overall, though, the chapter and verse divisions are very helpful.
The chapter divisions commonly used today were developed by Stephen Langton, an Archbishop of Canterbury. Langton put the modern chapter divisions into place in around A.D. 1227. The Wycliffe English Bible of 1382 was the first Bible to use this chapter pattern. Since the Wycliffe Bible, nearly all Bible translations have followed Langton's chapter divisions.
The Hebrew Old Testament was divided into verses by a Jewish rabbi by the name of Nathan in A.D. 1448. Robert Estienne, who was also known as Stephanus, was the first to divide the New Testament into standard numbered verses, in 1555. Stephanus essentially used Nathan's verse divisions for the Old Testament. Since that time, beginning with the Geneva Bible, the chapter and verse divisions employed by Stephanus have been accepted into nearly all the Bible versions.