Good and evil are two words used to describe certain actions or behavior exhibited by people. They are usually products of one's judgment about anything. Good is usually used to describe what is right or something that is beneficial to people or something that is acting in the common interest of people.
It is believed that the word evil is used for behaviors that are the enemy of good. So, we use evil to describe any action or behavior that can harm other people. At times, we tend to label some actions as evil or good based on how they occur to us, and not necessarily because they are naturally good or evil.
Also, my action to someone might be considered evil, whereas it can be considered good if the same action is exhibited in another situation. Our decision to label something as evil or good is usually influenced by our beliefs, culture, the result produced by the exhibited behavior, etc.