The Catechism in Questions & Answers

561. Who will be caught up at the return of Christ?

The rapture at the return of Christ is first of all promised to those who have been granted the rebirth out of water and the Spirit, who believe in Jesus Christ, and who follow Him. This group is also called the “bridal congregation” or the “male child” (Revelation 12: 5).
Whether God will also grant the grace of the rapture to others is beyond human judgement and is subject to the decision of God.

Rebirth out of water and the Spirit: see Question 528.

The ‘rapture’ (or the event of being “caught up to God”) means that human beings will enter into direct fellowship with God at the return of Christ.