What is the ruling on a woman whose marriage contract has been written, but who has not yet consummated the marriage, traveling without her fiancé's permission and without a mahram, when there is no necessity?

A wife is not obliged to obey her husband until she moves in with him and he provides for her maintenance. If she is in her father's house, under his guardianship and maintenance, then her husband's permission is not required for her to travel. It is not permissible for a woman to travel without a mahram, even if her husband gives permission, due to the saying of the Prophet, peace and blessings be upon him: "It is not lawful for a woman who believes in Allah and the Last Day to travel for a day's journey unless she is accompanied by a mahram."