Non-ionizing radiation is like a kind of light that doesn't have enough power to break apart the tiny parts that make up your body's cells. It's different from ionizing radiation which is much stronger and can damage your cells by breaking them apart.
Think of it like a ballerina who is very gentle when she touches you, she won't hurt you, but a wrestler who is very strong might accidentally hurt you. Non-ionizing radiation is like the gentle touch of a ballerina, it can't hurt your body's cells but it can still affect them a little bit. Examples of sources of non-ionizing radiation include sunlight, microwaves, and radio waves.
While non-ionizing radiation is not as dangerous as ionizing radiation, it's still important to be careful around it. For example, you should wear sunscreen when you go outside because too much sunlight can damage your skin. And you should never stare too long at a microwave or a television screen because the non-ionizing radiation they emit can still be harmful to your eyes if you do it for too long.