The FCC dropped the license requirement about 15 years ago for most civilian communication use, and the handheld market really took off.
Before that, you had to be certified... know Morse code, frequency theory, etc. Anyway, we're limited in the U.S. to the 60-meter (5 MHz)
band UHF/VHF frequencies alotted for that use. My boat radio has 128 channels and operates at up to 70 watts, useful when far from shore.
Most handhelds are about 5 watts but the limiting factor is batteries.