Lent is a tradition that was started by Christians many years ago with the goal of helping believers prepare for the celebration of Easter. It encompasses about 6 weeks (40 days) and begins at Ash Wednesday and ends the Saturday before Easter. (Ash Wednesday was so named after the practice of making the sign of the cross on one's forehead with ashes. It was literally the Day of Ashes.)
Lent is usually observed by churches that are more liturgical in practice (churches that follow ritual and tradition), and involves a 40 day period of fasting, repentance and reflection leading up to the celebration of Easter. Modern Evangelical churches typically do not observe Lent since they tend to de-emphasize non-biblical traditions.
The Bible says nothing about the Lenten season of preparation.