Light is electromagnetic radiation and exhbits dual nature, wave and particle.
if you consider light is wave, intensity is related to light radiation energy and frequency is the number of waves per second.
if you consider light is particle, each particle in the light radiation is called photon. Frequency is related to photon's energy (E = hν , E is energy, h is planck's constant and ν is frequency) . In particle nature, intensity is related to number of photons in the radiation.