§1. A minor necessarily retains the domicile and quasi-domicile of the one to whose power the minor is subject. A minor who is no longer an infant can also acquire a quasi-domicile of one’s own; a minor who is legitimately emancipated according to the norm of civil law can also acquire a domicile of one’s own.
§2. Whoever for some other reason than minority has been placed legitimately under the guardianship or care of another has the domicile and quasi-domicile of the guardian or curator.
Source: Code of Canon Law (Vatican.va)