Q. How do you use "~ san," "~ kun" and "~ chan"?
A. "~ san （～さん）" is a title of respect added to a name. It can be used with both male and female names, and with either surnames or given names. It can also be attached to the name of occupations and titles.
"~ kun （～君）" is used to address men who are younger or the same age as the speaker. A male might address female inferiors by "~ kun," usually in schools or companies. It can be attached to both surnames and given names. It is less polite than "~ san." It isn't used between women or when addressing one's superiors.
"~ chan （～ちゃん）" is often attached to children's names when calling them by their given names. It can also be attached to kinship terms in a childish language.