The Old Testament prophets Isaiah and Ezekiel both wrote about what they saw when they glanced into Heaven. But it's the New Testament writer, John, who tells the details of Heaven in his Revelation.
From the fourth chapter through the last chapter, 22, John tells what he saw in heaven.
In the middle of Heaven is a throne and God is sitting there surrounded by 24 elders sitting on smaller thrones. Angels and other beings, some with wings and different animal heads, fly around the area. Jesus is there appearing as a lamb whose throat was slit as a sacrifice. Also present are those who have been faithful to God and Jesus, where on their foreheads a new name is placed.
There is also a promise in Revelation 7:9-12 that says the followers of the Lamb will serve him:
Therefore, they are before the throne of God and serve Him day and night in His Temple. And he who sits on the throne will dwell among them. They shall neither hunger anymore, nor thirst anymore; the sun shall not strike them, or any heat; for the Lamb who is in the midst of the throne will Shepherd them and lead them to living fountains of water. And God will wipe away every tear from their eyes.
That promise is repeated in Revelation, chapter 21. There Heaven is described as a large city, with jewels and pearls for its foundation and gates. Gold is used for the streets and Jesus is the light.
Then the final promise, that God's servants will see His face and His name shall be on their foreheads. Revelation 22:4.