Bukhari

Hadith Commentary:
The hair of a deceased woman can be untied before the ritual bath (ghusl).
The benefit of this is that water reaches the roots and it becomes easier to clean the hair.
Similarly, if a man had kept long hair, then after his death, his hair can also be untied at the time of giving him the ritual bath (ghusl).
(Fath al-Bari: 3/170)
In brief, the following matters should be observed when giving the deceased the ritual bath (ghusl):
➊ The deceased should first be given istinja (cleaning of the private parts) and then ablution (wudu).
His nose and mouth should be cleaned with cotton, etc.
➋ Leaves of the lote tree (sidr) should be added to the water for the ritual bath (ghusl), and then it should be boiled.
➌ If the deceased is a man, then a religious and trustworthy man should be arranged for, and if it is a woman, then a woman possessing these qualities should be arranged for.
➍ The deceased should be given the ritual bath (ghusl) at least three times; if needed, it can be done more times, but an odd number should be observed.
➎ When pouring water for the last time, some camphor or any fragrance should be added to it.
➏ The woman’s hair should be untied and washed thoroughly, then combed.
➐ Finally, her hair should be braided into three plaits and placed behind her.
All these matters are established by evidences.
Allamah al-Albani rahimahullah has explained them in detail.
(Ahkam al-Jana'iz: 48)