Contact a military recruiter directly for more information about a particular branch.
AIR FORCE: http://www.af.mil/
COAST GUARD: https://www.uscg.mil/
Each branch of the service has a specific set of courses and training that officers must complete prior to joining. ROTC programs allow students to do this while completing their college education. Upon graduation members are commissioned (certified) by the President of the United States to serve as a leader in active, reserve, or guard components of each branch.