All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is permissible for a woman to beautify herself for her husband by adorning the body parts that usually appear, such as the hands, legs, face, hair of the head, and so on.
As for the hidden areas of her body, if there is something stated about it in the Sunnah, then one should adhere to it because it implies all goodness and guidance. However, if there is nothing stated about it, then she can apply whatever adornment she likes, as long as it does not involve imitating non-Muslim or immoral women, nor cause harm to her health. According to the Sunnah, the pubic hair should be shaved. It should neither be dyed nor have henna applied to it. That is because doing this entails leaving the pubic hair wholly or partially, which goes against the Sunnah.
It was narrated on the authority of Abu Hurayrah that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said: "Five practices are characteristics of the Fitrah (natural disposition): circumcision, shaving the pubic area, plucking the armpit hair, clipping the nails and cutting the moustaches short." [Al-Bukhari and Muslim]
It was also explicitly stated, in the Hadeeth narrated by Ibn ‘Umar that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said: "To shave the pubic hair, to clip the nails and to cut the moustaches short are characteristics of the Fitrah." [Al-Bukhari]
Allaah Knows best.