Fevronia’s name day is June 25, the feast of Febronia.
Churches that follow the Old (Julian) Calendar keep the same feast on July 8 of the civil calendar. See everything commemorated on June 25.
The saint behind the name

Febronia
June 25, Holy Woman, Φεβρωνία
St. Febronia was a young nun of Mesopotamia who suffered for Christ at the beginning of the fourth century, in the persecution of Diocletian. Raised in a monastery from childhood, she was famed for her beauty, her wisdom, and her love of the Scriptures. When the persecutors seized her, she refused the offer of marriage and freedom in exchange for denying Christ, and endured a cruel martyrdom with unbroken faith.
Also celebrating on June 25
These names share the feast, many of them other forms of the same name:
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.