Who is Holy Spirit?

Holy Spirit is the third member of the Godhead. He is not an it. His name is Holy Spirit. In Genesis 1:2 In creation when God spoke, it was Holy Spirit that moved on the face of the waters.
Luke 1:35 tells us that the angel explained to Mary, “The Holy Spirit will come on you, and the power of the Most High will overshadow you. So the holy one to be born will be called the Son of God.”
Matthew 3:13-17 Jesus came to John Baptist to be baptized by him. After John had baptized him, Jesus came out of the water and the heavens opened. He saw the Spirit of God descending like a dove and lighting upon Jesus. A voice from heaven said, “This is my beloved Son, in whom I am well pleased.
1 Corinthians 13: 14 The grace of the Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost, be with you all. Amen.
Matthew 28:19 Jesus told them to teach all nations, baptizing them in the name of the Father, and the Son, and of the Holy Ghost.
John 14:16-17 Jesus said, I will ask the Father, and he will give you another comforter to help you and be with you forever–the Spirit of truth. The world cannot accept him, because it neither sees him nor knows him. But you know him, for he lives with you and will be in you.
2 Corinthians 1:21-22 Now he which stablisheth us with you in Christ, and hath anointed us, is God; Who hath also sealed us, and given the earnest of the Spirit in our hearts.
Jesus told them I will send the promise of my Father upon you: waith in the city of Jerusalem until you are endued with power from on high. (Luke 24:49)
Acts 1:5 Jesus told them John baptized with water; but they would be baptized with the Holy Ghost not many days hence. Verse 8 he continued, you shall receive power, after the Holy Ghost is come on you;
Acts 2 tells the account of Holy Spirit filling all who were in the upper room and giving them power to speak with other tongues so that all who were in Jerusalem heard them speak in their own languages.
God has prophesied through Joel in Joel 2:28-29 he would pour out his Spirit on all flesh. In Acts 2 it is recorded where that prophecy was fulfilled. Verse 33 speaking of Jesus, after his resurrection, was exhalted and having received of the Father the promise of the Holy Ghost, shared it with them and they saw the results.
We see from these scriptures that Holy Spirit is God working through humans now. When scripture speaks of the baptism of the Holy Spirit, it is for the enduement of power to be witnesses. Jude spoke about praying in the Holy Ghost to build up their most holy faith.
Paul said, “Wherefore let him that speaketh in an unknown tongue pray that he may interpret. For if I pray in an unknown tongue, my spirit prayeth, but my understanding is unfruitful. What is it then? I will pray with the spirit, and I will pray with the understanding also: I will sing with the spirit, and I will sing with the understanding also.”

Holy Spirit works in the hearts of humans in many ways. There are Gifts of the Spirit, Ministry Gifts and Administrative Gifts in addition to the fruit of the Spirit. These are not the same thing.