Is covering the face for a women wajib or sunnah? In my country alot of ustazah did not adhere to wearing a niqab, can I learn deen from them?

Allah Taãla mentions in the Noble Qur'an, '(O Muhammad (Sallallaahu Alayhi Wasallam), tell the believing males to lower their gazes. tell the believing females to lower their gazes ...' (Quran 24:29-30). The injunction of lowering the gaze is clear that it is not permissible for strange males and females to look at one another. Due to the immorality of times and weakness of resistance, it is compulsory for a female to cover her face which is the focus of her beauty. The covering of the face conveniently facilitates the accomplishment of the purpose of lowering the gaze. and Allah Ta'ala Knows Best Mufti Ebrahim Desai