Filippa’s name day is November 14, the feast of Philip the Apostle.
Churches that follow the Old (Julian) Calendar keep the same feast on November 27 of the civil calendar. See everything commemorated on November 14.
The saint behind the name

Philip the Apostle
November 14, Apostle, Φίλιππος ο Απόστολος
The holy apostle Philip, one of the Twelve, was from Bethsaida of Galilee, the city of Peter and Andrew. Called by the Lord Himself, he brought Nathanael to Christ with the words Come and see, and in the Gospel of John he asks the Lord to show the disciples the Father. After Pentecost he preached the Gospel in Asia Minor and, according to tradition, ended his life as a martyr at Hierapolis.
Name days: Filippos, Filipis, Philip, Philippos, Phil, Filippo, Filippa, Philippa
Also celebrating on November 14
These names share the feast, many of them other forms of the same name:
Filippos, Filipis, Philip, Philippos, Phil, Filippo, Philippa
What to say on a name day
The Greek wish is Χρόνια Πολλά (Chronia Polla), “many years.” A call or a short message on the day is what people remember. See name day wishes you can send and what a name day is.