The Catechism in Questions & Answers

424. What commission did Jesus Christ give to the Apostles?

Apostles have been sent by Jesus Christ in order to grant human beings access to the sacrifice brought by Him and the salvation resulting from it.
After His resurrection Jesus gave the Apostles authority to proclaim forgiveness of sins. By His commission they are also to dispense the sacraments, proclaim the gospel, and prepare the believers for His return.