Philip (Philippos). The deacon (Act 6:5) and evangelist (Act 21:8), not the apostle of the same name (Mar 3:18).
To the city of Samaria (eis tēn polin tēs Samarias). Genitive of apposition. Samaria is the name of the city here. This is the first instance cited of the expansion noted in Act 8:4. Jesus had an early and fruitful ministry in Samaria (John 4), though the twelve were forbidden to go into a Samaritan city during the third tour of Galilee (Mat 10:5), a temporary prohibition withdrawn before Jesus ascended on high (Act 1:8).
Proclaimed (ekērussen). Imperfect active, began to preach and kept on at it. Note euaggelizomenoi in Act 8:4of missionaries of good news (Page) while ekērussen here presents the preacher as a herald. He is also a teacher (didaskalos) like Jesus. Luke probably obtained valuable information from Philip and his daughters about these early days when in his home in Caesarea (Act 21:8).