"Islam does not require women to participate in trade, the vocations or professions unless it is very necessary."1 In the case that she must work outside the home, she must work in fields that are lawful.
Those areas that would be considered unlawful are a dancer, a model, a barmaid, a waitress, a film actress, a musician, or a prostitute to sell her feminity in order to make money,2
Most other forms of work would be considered lawful as long as she adheres to Islamic principles in respect to dress and modesty.
Women and men working together can lead to trouble and therefore a woman should seek employment in a female environment.