Acceptable, when clearly relevant, to describe people with more than one racial heritage. Usually more useful when describing large, diverse groups of people than individuals. Avoid mixed-race, which can carry negative connotations, unless a story subject prefers the term. Be specific if possible, and then use biracial for people of two heritages or multiracial for those of two or more on subsequent references if needed. Examples: She has an African American father and a white mother instead of She is biracial. But: The study of biracial people showed a split in support along gender lines.
Multiracial can encompass people of any combination of races.