It is the day that Lent begins on which the faithful have blessed ashes distributed on their foreheads. Ashes are made from the olive branches or branches of other trees that were blessed the previous year during Palm or Passion Sunday.1
The beginning of the forty days of penance in the Roman Rite is marked with the austere symbol of ashes which are used in the Liturgy of Ash Wednesday. It is an ancient rite which converted sinners submitted themselves to penance, symbolizing fragility and mortality, and the need to be redeemed by the mercy of God. Far from being a merely external act, the Church has retained the use of ashes to symbolize that attitude of internal penance to which all the baptized are called during Lent.2
After the homily, the priest blesses the ashes and sprinkles them with holy water. Those present who come to him the priest will say:
Repent, and believe the Gospel.
Remember that you are dust, and to dust you shall return.
It largely depends on local custom. Some countries the prevailing custom seems to be that the priest places enough holy water into the ashes to form a kind of paste. The ashes are then daubed in the form of a cross on the forehead while others the sprinkling fairly dry ashes on the crown of the head.3
Blessing and distribution of ashes may also take place outside Mass. The rite is preceded by a Liturgy of the Word, with the Entrance Antiphon, the Collect, and the readings with their chants as at Mass. Then the homily and the blessing and distribution of ashes. It will be concluded with the Universal Prayer, the Blessing, and the Dismissal of the Faithful.
The blessing of the ashes is reserved to a priest or deacon and may be assisted by lay ministers in the distribution of ashes.
It is a matter of personal decision based on the individual's own inclinations and circumstances. The ashes can be left on until they wear off naturally or they can be washed off or wiped off when the individual chooses.
It may also be used when ashes are brought to the sick. The rite may be abbreviated by the minister, nevertheless, at least one Scripture reading should be included in the service. If already blessed ashes are brought to the sick, the blessing is omitted and the distribution takes place immediately after the homily.
It is not an obligation to attend the Mass, however, Ash Wednesday is a penitential day and it (together with Good Friday) is one of two days of the year on which fasting and abstinence are required.