Why was writing developed? and What key events of features of civilizations enabled people to develop writing?

The writing was invented and developed with the purpose of being able to express yourself, to send messages that have the exact same content as the author wants to, and to preserve the cultural and historic events.

The biggest contributor for the writing to be developed was the fact that the humans started to be engaged in agriculture and make permanent settlements. This allowed the people to have enough food and even surplus, so when that worry was set aside, the people had much more spare time and they were able to focus on other things apart from sheer survival, so the writing was one of those things that were the product of it.