How many frequency of power?

It depends on what you are talking about. In the beginning, a lot of frequencies were tried, 133 cycles per second being the most common. (There was only one company at this point.) Nikola Tesla designed his motors to run at 110 volts and 60 cycles per second, so that eventually became the standard in the USA. In Europe they preferred 50 cycles per second at various voltages. When airplanes were developed, they used 120 volts and 400 cycles per second because that requires a lot less iron. Some people also tried 25 cycles per second, but that was abandoned because you can see the light bulbs flicker at that frequency. In recent times the expression "cycles per second" has been replaced by "Hertz".