Is it permissible for a wife to travel for study without her husband?

A woman is not permitted to travel without a mahram, based on the Prophet’s (peace be upon him) saying: "A woman shall not travel except with a mahram." Exceptions to this include travel for obligatory Hajj and Umrah with a trustworthy group, and in cases of necessity, such as migration from a land of disbelief (dar al-kufr). Completing studies is not considered a necessity that permits travel without a mahram.