Now the question of who is the target audience for Job is a tricky one, because there is the audience that Job intended, and the audience that God intended. Since the book is not addressed to a group as are Paul's letters, or to a son as is the Book of Proverbs, or to Theophilus as are Luke and Acts, the best clues come from understanding the purpose of the book.
In Job 19, the suffering man says this:
23 “Oh that my words were written!
Oh that they were inscribed in a book!
24 Oh that with an iron pen and lead
they were engraved in the rock forever!
25 For I know that my Redeemer lives,
and at the last he will stand upon the earth.
26 And after my skin has been thus destroyed,
yet in my flesh I shall see God,
27 whom I shall see for myself,
and my eyes shall behold, and not another.
My heart faints within me!
Job wanted the world to know that he believed that God would raise him from the dead.
God wanted the world to know that Job spoke the truth about Him:
7 After the Lord had spoken these words to Job, the Lord said to
Eliphaz the Temanite: “My anger burns against you and against your two
friends, for you have not spoken of me what is right, as my servant
Job has. (Job 42:7)
And what was this truth that Job spoke? If you read Job's speeches carefully, you will see that out of his suffering he speaks prophetically about the coming savior and about many other events that were to come to pass. Evidence in the book points to it being written between the times of Abraham and Moses. The book is filled with examples of the several approved ways that God communicates with mankind, including sacrifice, looking for clues in nature, listening to wise elders, prayer, fasting, sabbath observance, dreams, visions, suffering, angels, and theophany. Job's prayer in chapter 19 cited above is a new contribution: the Word of God in written form. Just as Abraham prayed for a son and was blessed to become the father of many nations, so Job's prayer was answered beyond his wildest expectation: his story would become the first book of the Bible to be written down.
Job's main prophecy was that God was about to construct a written record of his dealings with mankind so that all people could know clearly what God expected of them and how to seek his favor. Thus Job's audience in general was the whole world. But in particular, you will see that many verses in Proverbs have their echo in Job, as do the Psalms, Ecclesiastes, Jeremiah, Revelation and even the words of Jesus in the Gospels. So another important audience was the prophets.
Amos said this in 3:7:
“For the Lord God does nothing
without revealing his secret
to his servants the prophets."
If Job is the first book in the Bible, then it stands to reason that, in addition to words about what would happen in the distant future, Job would leave instructions to guide people by telling them what would happen in the near future, to authenticate his next prophet. And so he does. The Bible has many references to papyrus as a symbol of the fragility of life.
Can **papyrus** grow tall where there is no marsh?
Can reeds thrive without water? (Job 8:11)
Which will be reversed when the savior comes:
The burning sand will become a pool,
the thirsty ground bubbling springs.
In the haunts where jackals once lay,
grass and reeds and **papyrus** will grow. (Isaiah 35:7)
Papyrus when formed into a swift boat is used to describe people trying to outrun God's judgment:
Woe to the land of whirring wings
along the rivers of Cush,
2 which sends envoys by sea
in **papyrus** boats over the water. (Isaiah 18:2)
In a chapter where Job says he cannot see God, he speaks of God walking on the seas:
He alone stretches out the heavens
and treads on the waves of the sea. (Job 9:8)
This is ironic, since a man who says he cannot see God has just given a prophecy of Jesus walking on water! (Saint John Chrysostom noted this centuries ago.) In that same chapter, Job says this:
“My days are swifter than a runner;
they fly away without a glimpse of joy.
26 They skim past like boats of **papyrus**,
like eagles swooping down on their prey. (Job 9:26)
Job speaks of a swift papyrus boat as reflecting how fast his life is moving towards death. The context is the midst of a storm:
He would crush me with a storm
and multiply my wounds for no reason. (Job 9:17)
Would you want to weather a storm in a boat made of papyrus? Not safe! So Job gives the image of a swift boat made of a material not fit for stormy weather, a material that cannot save him from a swift death. So can a papyrus boat save someone marked for death? Can the Lord make Job's words ironic and deliver a soul from a watery grave?
3 But when she could hide him no longer, she got a papyrus basket
for him and coated it with tar and pitch. Then she placed the child in
it and put it among the reeds along the bank of the Nile. Exodus 2:3
Who was placed in a papyrus basket and saved from drowning in the Nile? Moses!
So I would say that the immediate audience for Job was the Hebrew people, to endorse their great prophet, Moses, a man who would pen a large part of the Old Testament, and likely do so on scrolls made of papyrus.