During Prayer, one’s body should be decently covered, particularly the private parts and the areas around them. In case of men, this can be defined as an area of body beginning from the navel down to the end of the knee-cap. As far as women are concerned, they should cover their entire body, including their arms but excluding the hands and feet. However, when praying at home or among other women, they do not have to cover their faces.
According to most schools of Jurisprudence, men should cover their heads when praying. But the Malikis and a few others do not consider this necessary.