The Holy Spirit is the third person in the Trinity. He is fully God. He is eternal, omniscient, omnipresent, has a will, and can speak. He is alive. He is a person. He is not particularly visible in the Bible because His ministry is to bear witness of Jesus (John 15:26).
Some cults like theJehovah's Witnessessay that the Holy Spirit is nothing more than a force (Reasoning from the Scriptures, 1985, pp. 406-407). This is false. If the Holy Spirit were merely a force, then He could not speak (Acts 13:2); He could not be grieved (Eph. 4:30); and He would not have a will (1 Cor. 12:11).
The truth is that the Holy Spirit is a person the same as the Father and the Son are within theTrinity.