In modern times there are mainly three forms of ecclesiastical government used by different Christian denominations around the world.
Most common in the new American Evangelical Churches, Independent or Community Churches.
A single Pastor is in charge of a specific congregation, who may be assisted by a local committee. They are elected by the whole congregations and all major decisions must be presented and approved by the whole Congregation in free elections.
The Biblical model is based on the example of Acts 6:2-3 when the Apostles asked the whole congregation to elect seven deacons to help them in their catering duties.
Use mainly by Reformed Churches were the government is entrusted to a group of Elders of the local Church, either commissioned as fultime ministers or not; and generally a delegation of them form a national assembly that would manage the whole denomination on a national level.
The Biblical model is based on the accounts of Acts 14:23 and 15:4, 6 where a number of Elders were in charge of a congregation and came together in council to solve problems and manage the whole church.
The system used by all apostolic Churches, that is Roman Catholic, Eastern Orthodox, Oriental Orthodox, Assyrians, Anglicans and Episcopal Lutherans.
In this system, a whole geographical area is under the management of a Bishop, who has under him a series of parishes or local congregations under the control of one or two presbyters and Deacons.
Usually, a local number of dioceses under a Bishop elect one of their own to represent the whole denomination on a larger scale, and name him Archbishop or Metropolitan.
Roman Catholics and Orthodox have also variations over this level not necessary to deal with at this moment.
The Biblical model is the accounts of Timothy and Titus and 1 John 1:9, where a middle class of authority is found to be in existence below the Apostles but above the Elders.
(Titus 1:5; 1Timothy 4:11)
WHICH MODEL IS THE CORRECT MODEL
Since the Reformation, every Christian reformed groups and their offshoots have claimed Biblical reason for their system of government or have declared that the Scripture does not condone one in favour of another, so that all models are correct and acceptable.
The Congregational and Presbyterian models shown in the Scripture are only historical accounts of Christian communities’ government during a period of evolution.
First only the Apostles managed the whole congregation; then Deacons came into existence, and later groups of Elders who stayed stationary in local communities to manage the day to day discipleship of Christians while the Apostles moved from one country to another.
By the end of the First century, as the Apostles slowly passed away, they took care to established persons in charge, with full authority, to manage whole regions under the pastoral care of the Elders. This in time came to be known as Overseers or Bishops, a name originally given to all Elders. Also, there were a few forms of Presbyterian governments that slowly were taken over by this newly born Episcopal system.
However, it seems to be the Episcopal System, the one the Christian Church has used uninterrupted for 2000 years to this day.