Is it obligatory for a woman to wear a prayer skirt over trousers during prayer, and what should she do if she is outside her home; should she pray without it or carry one with her?

It is permissible for a woman to pray in loose trousers that do not reveal the shape of her body. However, if they are tight, it is disliked for her to pray in them if she is far from non-mahram men, and it is recommended for her to wear an outer garment (dir', like a loose dress or cloak) over them. But if non-mahram men can see her, it is impermissible for her to wear them and pray in them.