The leadership offices of Deacons (1Timothy 3:8-13) and Elders are necessary in the church. They assist the leaders in the church ministry gift offices. Deacons are called to serve or assist the ministers in carrying out their roles (Acts 6:1-6). The female equivalent of deacons is deaconesses who may be wives of ministers or other women in the church who serve in ministry or church as helpers to leaders (Romans 16:1-2).
Elders are leaders who assist in decision making and see to the needs of various groups in the church (Acts 14:23). They help to develop local bodies of believers (Titus1:5-9). Elders are to assist the ministry gift leaders in developing biblical body of believers (Titus 1:17; James 5:14).
No one is called into ministry to be an elder or deacon but is appointed by church leaders as led by the Holy Spirit. However, believers could be called to be teachers, prophets, evangelists etc as a leadership ministry gift.