Discipleship, it's main goal is to gain souls for Jesus Christ. Discipleship is one way to share God's Word, gain souls for Christ, spreading the Gospel, mentoring future discipleship leaders and more, much more.
For me, Discipleship is the obedience you gave to your leader. Disciple means as a follower. In the Bible, Jesus has followers and he call them as his disciples. Discipleship also means as being loyal to only one God and following his all commands. Discipleship also help people to strengthen their faith and trust to God.