“Exactly how many heavens are there and what is the purpose of each realm?”
We believe the Scriptures teach there are three heavens.
The first heaven is our atmosphere where we live and serve the Lord. It is where the Psalmist says, “the fowls of the heaven have their habitation, which sing among the branches” (Psa. 104:12).
The second heaven is the solar system that consists of the sun, moon, stars, and planets (Gen. 1:14-18). Prior to the written revelation of God, the Lord used this realm as a teaching tool. Once again, in the words of the Psalmist, “The heavens declare the glory of God; and the firmament [expanse] sheweth His handiwork. Day unto day uttereth speech, and night unto night sheweth knowledge” (Psa. 19:1,2). While Satan currently dwells in the second heaven, he will be cast out of heaven to the earth in the middle of the Tribulation period (Rev. 12:7-12). Throughout eternity, the members of the Body of Christ will occupy this realm and its various seats of authority (Eph. 2:6).
The third heaven is the abode of God often referred to in the Scriptures as the heaven of heavens. It is also where an innumerable host of angels worship and serve the Lord. This is confirmed by Nehemiah, “Thou, even thou, art Lord alone; thou hast made heaven, the heaven of heavens, with all their host, the earth, and all things that are therein” (Neh. 9:6).
Paul reveals that he was caught up to the “third heaven” where he received a further revelation from the Lord regarding the Mystery (II Cor. 12:1-4; Eph. 3:2,3). The apostle also calls this realm Paradise. Today, we have a heavenly hope according to Colossians 1:5; therefore, when we come face to face with death, we look forward with great expectation to be absent from the body “and to be present with the Lord” (II Cor. 5:6-9), Who dwells in the heaven of heavens. source