Within the structures mentioned above, after becoming followers, adherents have many ways of serving which Religious Laws reserve for them. They may enter either the Cửu Trùng Ðài/the Executive Body or the Hiệp Thiên Ðài/the Legislative Body. According to Pháp Chánh Truyền (The Religious Constitution of Caodaism), followers may be elected and hold a post if they can prove their capacity in terms of deeds, words and virtue. Nominations and promotions in the episcopal hierarchy are first submitted to the Popular Council/ Hội Nhơn  Sanh. Then they are submitted to the Sacerdotal Council/ Hội Thánh. They are also submitted to the High Council/Thuong Hoi, and finally must be approved by God or by the Spiritual Pope Li T'ai Pai (Đức Lý Giáo Tông). Almost all the positions in the Caodaist hierarchy can be replaced by election, except those titles directly appointed by God (Đức Cao-Đài) or Divine Authority through spiritism (cơ bút). The high dignitaries of the Legislative Body (Hiệp Thiên Ðài) such as Hộ-Pháp, Thượng-Phẩm, Thượng–Sanh, and the twelve Lords of the Zodiac (Thập Nhị Thời Quân) are directly appointed by God.

According to Pháp Chánh Truyền /the Religious Constitution of Caodaism :

 "The dignitaries of the two Colleges (of Men and Women) of the Cửu Trùng Ðài/Executive Body are invested in the Temple of the Divine Alliance (Hiệp Thiên Ðài), either through their own merit, or through designation by means of a medium (direct investiture), or through an organised election before the dignitaries of the Hiệp Thiên Ðài, in order to avoid all fraud or partiality. What is more, with the assistance of these dignitaries it is permissible to consult the Spiritual Pope or Our Divine Master to know whether those elected are worthy of their rank. Thus before official notification, all dignitaries must be presented for the approval of the Giáo Tông/Pope or of our Divine Master".

• - "The Papal Throne/ Giáo Tông is in the power of Legislative Cardinals/ Chưởng-Pháp and the Cardinals/ Đầu-Sư through the universal vote of the adepts, except when the Giáo Tông/Pope is chosen by our Divine Master (direct investiture)".
• - "The Cardinals/ Đầu-Sư are elected to the rank of Legislative Cardinals/ Chưởng-Pháp through the vote of their colleagues (the other two Cardinals)".
• - "The Archbishops/ Phối-Sư are elected to the rank of Cardinal by the vote of their thirty-six colleagues".
• - "The Bishops/ Giáo-Sư are elected to the rank of Archbishops by the vote of their seventy-two colleagues".
• - "The Priests/ Giáo-Hữu are elected to the rank of Bishops by the vote of their 3000 colleagues".
• - "The Student-Priests/ Lễ-Sanh are elected to the rank of Priests by the vote of all their colleagues".
• - "The disciples who aspire to the rank of Student-Priest are elected by the vote of all Faithful, except in the situation when dignitaries are chosen by Divine Voice".
• - "The Chánh-Trị-Sự  (Minor Office-Bearers, Village Religious Chief) are elected by the vote of Phó-Trị-Sự (Deputy Chief for Administration of a religious village) and Thông-Sự (representing the Legislative Body). The Phó-Trị-Sự and Thông-Sự are elected by the vote of the adepts".

Under Hiệp Thiên Ðài/Legislative Body, Phước Thiện /the Charitable Organisation is another way of serving in Caodaism. That is the path of twelve divine ranks (Minh Đức , Tân Dân, Thính Thiện, Hành Thiện G iáo Thiện, Chí Thiện, Đạo Nhơn ,  Chơn Nhơn, Hiền Nhơn, Thánh Nhơn, Tiên Tử, Phật Tử). The total number of dignitaries in each rank of the Charitable Organisation is unlimited. A follower who has fulfilled his/her duty for three years may be raised to the next rank. The Charitable Organisation is the major agency for social services. At the Holy See, the Charitable Organisation has responsibility for and supervision of a hospital, homes for the elderly, an orphanage, the high school, musicians, acolytes and choristers. The Organisation's official representatives operate at the same levels as the Executive Body, and each local congregation has a "local charitable committee" (Bàn Cai Quản) whose responsibility is to care for the social needs of the local community. The "local charitable committees" with believers normally build Điện Thờ  Phật Mẫu/Holy Mother Temples for the dedication of worship of the Holy Mother (Universal Mother/ Đức Phật Mẫu).