The traditional date of Epiphany is January 6, but in the United States it is celebrated on the Sunday between January 2 and January 8. Epiphany celebrates when the three Magi came to visit Jesus bringing gifts of gold, frankincense, and myrrh.

As the Magi visited Jesus in his home, it is a tradition to bless your home using chalk to inscribe the date and the initials of the three Magi (Caspar, Melchior, and Balthasar), which are also the initials of the phrase "Christ bless this house" in Latin: Christus mansionem benedicat.
This year we write 20+C+M+B+21

See the document below for a prayer service for your family.