Is it unlawful for a wife to work as a beautician (makeup and skin treatments) in a women's salon, bearing in mind that she does not perform epilation and helps with living expenses, and has no other profession?

There is no objection to a woman working in a beauty salon as an expert or beautician, provided that she does not do what is forbidden by Sharia, such as plucking eyebrows (al-Nams) or hair extensions. Also, she should not beautify someone if she knows or strongly suspects that the person will display her adornments immodestly (tabarruj), because this is considered cooperation in sin. Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression."