Jesus picked 12. We know about Judas Iscariot; he’s the betrayer. We know about Peter, James and John — they were the inner circle. They were taken when the other nine were left behind.
The hand-picked 12 disciples became the 12 apostles (subtract Judas Iscariot and add Matthias). The book of Acts tells us about their important work in laying the foundation of the church.
But what is interesting — at least I think it is — is that, starting with chapter two, only three of the apostles are mentioned by name, Peter, James and John.