When reading through the Acts of the Apostles, chapters 6 and 8 can be confusing, as they mention a man named Philip, and at first glance he appears to be one of the original twelve.
However, when those passages are more closely examined, they reveal an entirely different person, often referred to as Philip the Deacon.
The key to identifying Philip the Deacon is to read the following passage from the Acts of the Apostles.
Now in these days when the disciples were increasing in number ... And the twelve summoned the body of the disciples and said, “It is not right that we should give up preaching the word of God to serve tables. Therefore, brethren, pick out from among you seven men of good repute, full of the Spirit and of wisdom, whom we may appoint to this duty ... and they chose Stephen, a man full of faith and of the Holy Spirit, and Philip, and Prochorus, and Nicanor, and Timon, and Parmenas, and Nicolaus, a proselyte of Antioch. These they set before the apostles, and they prayed and laid their hands upon them.
Acts 6:1-6
In chapter 8, this same Philip is mentioned, along with various encounters he had, such as with Simon the magician and the Ethiopian eunuch.
These passages are all we have about Philip the Deacon, though he was later celebrated as a saint.
St. Philip the Deacon's feast day in the Roman Rite is October 11, though it is not on the universal calendar of the Church.