Radio spectrum, which is broken up into service like television, cellphone, and broadcast radio. is controlled by the individual countries and an International Telecommunications Union and then granted to the different services or companies that use radio. For the most part, spectrum is very expensive. Companies like Verizon and AT&T pay billions of dollars for spectrum on which they run cellphone systems. Amateur Radio gets spectrum for free with the condition that the radio operators follow certain, relatively easy, rules.
In the United States a good place to go to read more about Amateur Radio is
the American Radio Relay League, or ARRL.
In Canada the Radio Amateurs of Canada.
In Great Britain, the Radio Society of Great Britain
There are also local clubs in most cities and at parish and county level in much of the world.