Each local congregation of the Lord’s Church is overseen by 2 or more elders (Acts 14:23). Each one of these men must meet the qualifications set forth in 1st Timothy chapter 3 and Titus chapter 1. Their oversight is limited to their local congregation.
A local congregation can have any number of deacons. These are men who also must meet qualifications which are found in 1st Timothy chapter 3:8-13. Their work is a work of service for the congregation and the individual members who make it up. They also are under the oversight of the elders.