We all know parishes are typically governed by certain bodies. Of course, this ought to be the case. Every parish needs leaders to serve parishioners and churchgoers alike. A basic structure, therefore, is needed in any parish.
Below is the usual structure of parishes in order of rank.
The parish priest mainly governs over the parish as an extension of the diocese. He is responsible for the pastoral care entrusted to him, as well as the administrative duties of the parish as a whole. As such, he is expected to both be a pastor to churchgoers and a chief officer to everyone in the parochial realm.
The assistant priests—as their title implies—have that duty to take over whenever the parish priest is unavailable. They are usually assigned to celebrate Masses according to a certain schedule, when the parish priest may need time to attend to other matters. As such, they also have pastoral duties to the community.
Lay people are neither ordained nor consecrated, but some volunteer to help out in the local parish as officers. Lay ministers distribute hosts to churchgoers during communion and women may collect donations using baskets. Other lay people may also conduct activities and coordinate with the priests when doing so.
The religious include nuns and monks—those who aren’t ordained as priests, yet serve the parish nonetheless in any way they can. They may do as the lay people do, and also engage in tasks such as leading prayer services among others. For the most part, they are engaged in prayer and interior life.
Deacons are ones on their way to becoming priests, except they aren’t ordained yet. They may assist priests in conducting sacraments such as baptism, Holy Communion, and matrimony, but they aren’t allowed to celebrate so themselves. Instead, they may preach in behalf of the priests and become pastors in their own right.
Though different parishes have different structures, the basic foundation of every parochial body remains. If you’re unsure about the structure of your own parish, go on a visit and learn more yourself!
Parish, Catholic Encyclopedia (New Advent)
The Role of Priests in the Catholic Church, For Dummies.com