A. The simple answer to your question is yes. But perhaps ask this question because you or someone you know may have an interest in the priesthood. So allow me to give some more details to you about the whole process or preparing to become a priest.
If a young man begins preparing to become a priest right out of high school then the normal process would be to attend 4 years of college seminary followed by 4 years of graduate studies at a major seminary. At the college seminary the seminarian would typically get a bachelors degree in philosophy. Additionally he may study languages such as Latin, Greek and Spanish as well as some undergraduate studies in theology. Then, after graduation, he would attend a major seminary which will provide 4 years of graduate level studies in theology. This includes Doctrine, Canon Law, Church History, Scripture, Liturgy and more.
Sometimes it happens that someone has already received a bachelor degree in some other topic from a college other than a college seminary. In that case he can complete his studies in 6 additional years. First, he would study what we call pre-theology for 2 years. This is primarily philosophy. After that he would enter into major seminary and fulfill the studies I mentioned above.
It’s also important to note that there is a difference between a diocesan priest and a religious order priest. The process above is used for all diocesan priests but religious order priests may also have some additional formation period either before or during the seminary process. So, for example, a Franciscan may first spend time learning about the life of St. Francis and may need to be formed in the rule of the order before even beginning seminary studies. This is usually the case for all religious orders.
Lastly, I should point out that the process of becoming a priest involves much more than just studies. Throughout his time as a seminarian there will be an emphasis upon what we call spiritual, human and pastoral formation. Spiritual formation consists of retreats, times of regular prayer, the daily liturgies, spiritual direction and spiritual conferences. Human formation is a way of seeking to form the seminarians human personality so that his human qualities become a bridge to Christ for others. So, through conferences, spiritual direction and with the assistance of other formators the seminarian will be challenged to let grace transform the parts of his personality that need to become more like Christ. Pastoral formation consists of giving the seminarian opportunities to get involved in parish life, teaching, hospital ministry and the like. These experiences will help prepare him for the time when he must function as Christ’s priest.
Hope that helps! And if you, or someone you know, feels as though God is calling him to become a priest then I suggest the first step is to contact his pastor for some guidance. He can also contact the diocesan Vocation Director.