Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
It is not obligatory upon a woman to work in order to provide for her children if she has a husband. Because, it is the duty of the husband to provide for his wife and children. Even if the law in the country where you live is otherwise, as this is one of the Islamic religion principles which cannot be changed by man-made laws.
However, if the woman voluntarily takes up a job and provides for her home, then there is no harm in that. But a woman cannot do any job, as it is forbidden for her to mix with men as commonly noticed these days, It is forbidden for her to stay in seclusion with them speak to them in soft words, or show her beauty to them. So if the woman's work is free from the above prohibitions and the other prohibitions which contradict the Shariah, then there is no harm in taking up this job.
However, it is more appropriate for the spouses not to resort to this kind of situation unless the husband is unable to work. As it is the woman who is ordered to stay at home. Allah says: "And stay in your houses, and do not display yourselves like that of the times of ignorance…"(Al-Ahzab 33:33)
Allah knows best.