Ash Wednesday marks the beginning of Lent in the Catholic Church. Fasting means doing without something. The Bible says that Jesus spent 40 days in the desert fasting and praying. Lent is meant to remind us of this and therefore also lasts 40 days.
Because there is no fasting on Sundays and public holidays, the whole period lasts a little longer overall. Ash Wednesday is not on the same date every year. The exact day depends on when Easter is. Ash Wednesday is exactly on the 46th day before Easter Sunday. On Ash Wednesday, Catholics abstain from meat. This has led to the custom of eating fish on this day.
Ash Wednesday is so called because on this day the faithful have a cross of ashes drawn on their foreheads during the service in church. This is a reminder that everything passes and that death is also part of life. Carnival is celebrated in the days before, for example on Shrove Monday. The merry and exuberant carnival season ends, however, with Ash Wednesday.
Originally, Lent was only for believers, but now non-believers also fast. It is then a matter of consciously doing without something. What people fast can be very different, but it is something they do not like to do without: Some don't watch television, others don't eat sweets or meat.