"The Cause for beatification and canonization concerns a Catholic faithful who, during their lifetime, at the moment of death, and after death, has enjoyed a reputation for holiness, martyrdom, or the offering of their life.
For the opening of a Cause for beatification, the person’s “reputation for holiness” is therefore always required—that is, the common opinion among the people that his or her life was upright and rich in Christian virtues (...)".
From here begins the canonical process that marks the steps toward Holiness. This process is clearly explained by the Dicastery for the Causes of Saints of the Holy See on its official website. We invite you to read it.