Who was the first person to write the Bible?

Answer 1

The Bible had many authors. According to tradition, the earliest Books of the Hebrew Bible were written by Moses.

More information:

According to tradition, Moses wrote a scroll containing the narratives of Genesis, at God's command, before the formal Giving of the Torah (Rashi commentary, Exodus ch.24). It was this scroll which he read to the Israelites (Exodus 24:7) as an introduction to what God's covenant would entail. These narratives were not unknown to the Israelites, since they had carefully preserved the traditions of the events of the lives of Abraham, Isaac, and Jacob (see Midrash, Shemot Rabbah 5:18 and 22).
The words of this scroll were soon incorporated in the complete Torah itself by God, including the ancient traditions of the Creation, the Flood etc. (These traditions had been known by mankind worldwide, except that among the other nations [the idolaters] they had become garbled with idolatrous drivel.)
When God gave the Ten Commandments (Exodus ch.19-20), He gave them in writing, inscribed on stone tablets (Exodus 31:18), while He taught the rest of the Torah to Moses orally, on Mount Sinai (Exodus 24:12), without writing it.
At God's command and precise dictation (Deuteronomy 1:3), Moses penned the entire Torah (Deuteronomy 31:24) immediately before his death, so that it included events that had happened in the preceding months (such as Numbers ch.20).

No Hebrew copy of the Torah has ever been found to differ with the others, worldwide. The Torah we possess today contains the exact wording written by Moses.See also:

What is the history of the Hebrew Bible?

Answer 2

The Bible is a collection of texts written by various authors over a span of centuries. It is not attributed to any single person. Different books of the Bible were written by different authors, such as Moses, David, Solomon, prophets like Isaiah and Jeremiah, and many others.