For communication and records.
The Phoenicians developed their writing system from the Sumerian writing system in 1400 BCE, so their writing system came after the Sumerian one.
In the Phoenician city-states.
To keep readily and consistently readable and understandable records and communication.
In order to record and communicate in an economical and effective way, compared to existing pictograms and syllabic writing.
An alphabet.
No, the Phoenicians did not develop the Bible. The Bible is primarily a collection of texts from ancient Israelite culture and tradition, written by various authors over centuries. While the Phoenicians, known for their trade and writing system, influenced surrounding cultures, including the Israelites, they were not responsible for the creation of biblical scripture.
In order to record and communicate in an economical and effective way, compared to existing pictograms and syllabic writing.
The Alphabet
They were the first to develop alphabet-based writing, much simpler than the writing systems developed so far.
The Phoenicians improved upon the Sumerian invention by when the Sumerians invented the first writing system (symbols and cuneiform) the Phoenicians invented the alphabet which was easier.
They developed an alphabet to impr0ve on the cuneiform writing system.
An alphabetic system.