Non-Ionizing radiation does not carry enough energy to break molecular bonds and ionize atoms. Example of non-ionizing are Extremely Low Frequency (ELF) and Radio Frequency (RF) radiation.
Ionizing radiation is the type of radiation that carries enough energy to break bonds between molecules and ionize atoms. Examples of Ionizing radiation are the gamma rays emitted by radioactive materials, cosmic rays, and X-rays.
Read more about Non-Ionizing radiation and Ionizing Radiation.