Correct way to use ms and mrs?

Ms. (pronounced miz) may be used for any woman whether married or single. Mrs. (pronounced misus) is used to refer to a married or formerly married (divorced or widowed) woman in order to specify her marital state. Etiquette does not require either term of address and it is best to use the term a specific woman prefers, if known. If her marital status is unknown then it is best to use Ms. rather than Miss or Mrs.