Is it permissible for a girl to travel alone for study and work in a foreign country to secure her future and the future of her family, given that her father opposes her travel on the grounds of not having a mahram, and he does not care for her financial affairs? And would her travel be considered disobedience to her father?

Traveling to Western countries poses risks to a Muslim woman's faith. It is obligatory to obey your father by not traveling there, because obeying him in what is good is واجب (obligatory), and a father preventing travel in this situation is considered good. Piety towards Allah facilitates matters. Allah Almighty says: "And whoever fears Allah - He will make for him a way out And will provide for him from where he does not expect." The father must fulfill his responsibilities towards his children, especially females, and he should be advised and reminded of his responsibility before Allah Almighty.