Because the Bible is actually a collection of 66 books, it was written by many people (40 writers). Some major authors are Moses and Paul, who are credited with writing multiple books each. Each prophetic book in the Old Testament is typically credited to have been written by the person that it is named after, same with the Gospels. Acts was written by the same Luke who wrote the Gospel of Luke. Paul wrote almost all of the New Testament after Acts, except for the letters named after someone else, Hebrews (whose author is still unknown though many stating it belongs to Paul), and Revelation, which was written by John.
It is important to note, however, that the Bible is the 'inspired word of God' given to these particular writers for all our edifications (see 2 Timothy 3:16-17).