The Catechism in Questions & Answers

513. Who is entitled to partake in Holy Communion?

Those who have been baptised in the New Apostolic Church, those who have been sealed, and those who have been adopted into the congregation are entitled to regularly partake of Holy Communion.
Properly (rite) baptised Christians may also have access to Holy Communion as guests.

Holy Baptism with water: see Questions 404., 481. et seq. ‘Rite’: see explanation of Question 488. Holy Sealing: see Questions 404., 515. et seq. Adoption: see Questions 662., 669.