There are lots of ways to become a pilot. You can receive flight training from a flight school at your local airport. There are college programs where you earn a degree as well as earn your pilot license's. You can also train in the military.
I will explain how I got started. After I graduated from high school I went to a community college for two years where I was trained in the following programs: Student, Private, Commercial, Instrument, Multi Engine and Flight Instructor.
I then transferred my college credits to a second college where I earned a BS degree and earned money by flight instructing. This was a good way for me to train as a pilot, complete my four year college education and log flight hours in an airplane.
The other route is strictly civilian it basically starts as a light aircraft instructor you build time perhaps work for a charter operation and then maybe get hired by a connecting carrier airline works with one of the majors like Delta United or American the idea is to build as much flight time as you can in these jobs so that one of the major airlines will find you qualified