This chapter shows us a unique act in the history of humanity, "the empty tomb" Jesus has risen! The appearance of the risen Christ spared the fears of the disciples. They were convinced that He was the same Jesus who had been crucified a few days before, as proved by the wounds on his hands and side.
The commission given to the disciples to carry out the mission of Christ is what made them "apostles or envoys", the power to perform such a mission comes from the Holy Spirit, poured out on all believers at Pentecost; that is, they were commissioned with a mandate and a message, "world evangelization"
In these verses 20.21-23, John presents the deity of Jesus, the son of God, as God, He has created all things, and as God He has come to redeem all, to bring the fullness of divine forgiveness.