What is the difference between Bishop, Archbishop and Cardinal?


Cardinal 
When a bishop is appointed by the Pope to serve as a Cardinal, he continues in his role as the visible head of a (arch) diocese. He also becomes a close advisor of the Holy Father in matters of the Church and has the task of electing a Pope. Strengthened with a special outpouring of the Holy Spirit, through the imposition of hands, Bishops act as Christ’s representative as teacher, shepherd and priest.

Archbishop
When a bishop is appointed by the Pope to serve as Archbishop, he is made the visible head of an archdiocese. An archdiocese is a larger diocese, or one of historical importance. His primary task remains – to teach, govern and sanctify this flock.
Bishop 
When a priest is appointed by the Pope to serve as Bishop, he is ordained to the fullness of the sacrament of Holy Orders. He is made the visible head of a diocese. He is given the task to teach, govern and sanctify this flock.