There is a term of MOS or Military Occupation Specialty in the United States of Army. This is a system of categorization of work and subjects of the personnel that is related.

There is a Career Management Fields (CMF) that will mention about the career classifications of the Army groups. For example in the CMF of Artillery will contain about the MOS that mentioned about several points: specialist of fire support, member of canon team and member of system of the multiple launch rocket team. There are many classifications contains in the MOS of Army such as: air defense, military intelligence, military police, chemical corps, and many more. The personnel that join the Army will decide the MOS according to their interests at the moment they enroll in the military. If those applicants are still not sure about which career will they chose, there is a test called the Armed Forces Vocational Aptitude Battery that able to assist new member to guide for the interest. There will be a basic training which held in 14 weeks and afterward will be continued with the MOS training. The location of MOS training will be held in all over the country.

The laws that apply to any occupation have many different kinds of points; this is also valid to the military law. To enter the military there are several prerequisite that must be completed, those are like physical and mental criteria. One of the branches of the military service is the military police, which has a towering level of criterions. Here are several points of those criterions:

First, candidates must not have a wrong or crime or any imprisonment of over four months. It is not allowed if candidates have previous records of violence. Thos candidates must not have further than two traffic breaking laws in the 5 years before enrolling the application in the military. Second, candidates are not allowed to use any drugs or substances that are illegal or own such illegal substances. Third, all candidates must have strong and physical staying power. Forth, the particular capable military members will be appraised for the likelihood of operating the nuclear weapons, which will be in the Personnel Reliability Program. Fifth, there is a background investigation will be held to achieve the clearance of the confidential security. Sixth, applicants must succeed the training.