First of all, the Catholic Church has only three hierarchical degrees of Holy Orders, which means that of all the above only the Bishopric, the
Presbyterium (Priest) and the Diaconate are ordained ministries the rest are extra roles or simply religious states adopted by lay people.
To understand the roles of these ministries it is important to first understand the structure of the Church.
Every Catholic is familiar that the Church is grouped into Dioceses and Parishes. But what most people don’t know is there’s further grouping into Ecclesiastical provinces or Archdioceses. The head of such a province is the Archbishop which is basically a bishop who is appointed to an archdiocese. Which means, if a previously ordained Bishop gets appointed to an archdiocese he becomes an archbishop.
The Bishop is the head of a particular Church or a diocese and enjoys full Priestly Ministry. He ordains priests and deacons who help in the celebration of the Sacraments for the propagation of the Faith and the sustenance of the Church.
A Priest (Diocesan): is an ordained minister and is next in line after the Bishop. He heads a parish or fills some diocesan position in addition to his ordinary ministry which is the celebration of the Mass and the forgiveness of sins. His power flows from the Bishops and is ordered towards assisting him. A priest promises his bishop obedience at Ordination but does not take any vows at all.
A Friar-Priest is a member of a congregation, who is also ordained by a bishop. But unlike the diocesan priest, he takes the vow of obedience to his bishop and superiors. A friar isn’t necessarily a priest mind you. Some friars choose not to become priests.
A Deacon is the lowest of the Orders and is in service of the community. Usually, this is a transient phase since most deacons end up becoming priests. He cannot hear confessions or celebrate Mass but can administer many other Sacraments.
A Cardinal: is not a position one gets ordained to have rather it is a rank within the Church. A Cardinal is a “Prince”, from whose ranks the Pope is selected and who is also tasked with particularly helping the Pope govern the Church more closely. He is always available to answer the Pope and will remain for as long as he is needed. For one to be appointed a Cardinal by the Pope, he must first be an ordained priest. And before created Cardinal, he will be ordained Bishop if he isn’t.
A Monk: someone who chooses to retire in the wilderness for a life of work and prayer. They take the strictest of vows, the Cistercians, for instance, take five vows, while regular friars take only three. They live in Monasteries, cloisters and pray a lot. The head of an Abbey is called an Abbot and the head of a priory (another level of a monastery) is called a prior. So the monks vow obedience to their Abbots or priors among other vows. A monk can also be ordained to the priesthood by a bishop.
A Nun: is a woman who, like the monk or the friars choose to live even closer to God, in a community and forfeit the life of marriage and family. She cannot be ordained to any ministry but is tasked with prayer and several other works according to their religious congregations. They vow obedience to their abbess or superior.