Today 21 Feb' is Ash Wednesday

Ash Wednesday is the first day of Lent and occurs forty-six days before Easter.

At Masses and services of worship on this day, worshippers are blessed with ashes by the celebrating priest or minister. The priest or minister marks the forehead of each participant with black ashes, in the shape of a cross, which the worshipper traditionally retains until washing it off after sundown.

The priest or minister offers the worshipper an instruction while applying the ashes. These are three examples:

"Remember, man, that you are dust
And unto dust you shall return." Genesis 3:19.

or
"Turn away from sin and be faithful to the Gospel."
or
"Repent, and hear the good news."

The ashes are prepared by burning palm leaves from the previous year's Palm Sunday celebrations and mixing them with olive oil as a fixative.

In the Roman Catholic Church, Ash Wednesday is observed by fasting, abstinence (from meat), and repentance—a day of contemplating one's transgressions.
The ashes are sacramentals, not a sacrament.