I'm not sure if this is what you are asking, but they are also known as "the Daughters of Saint Bruno."
They were, and still are, the Carthusian Monks and Nuns who live (headquartered) near Grenoble, France.
Domenican sisters wear an all white habit, as do Cisterians nuns, and I believe Carthusian nuns.
Carthusian was created in 1084.
Portrait of a Carthusian was created in 1446.
Denis the Carthusian was born in 1402.
Denis the Carthusian died in 1471.
The motto of Carthusian is 'Stat crux dum volvitur orbis'.
Roman Catholic AnswerNo, it is not a requirement. Nuns belong to a particular monastery or religious order. Most nuns are Benedictine, Carmelite, Cistercian, or Carthusian. I'm sure that there are others, but these are the biggest and most well know. Each monastery has its own set of rules, although they usually have a charter or something in common. Many orders or monasteries require their nuns to be veiled, others do not. The Vatican has asked that all sisters and nuns wear veils, but unless their Order or their superior require it, there is little, normally, that Rome can do. Sisters are not nuns, but the answer is the same for them.
The Prior of a Carthusian Monastery.
Other nuns
Monks and nuns do the monks' and nuns' jobs now.
Yes, nuns can vote.