As far as Islamic Shari`ah is concerned, Muslim males are recommended to take care of their hair. The Prophet (peace and blessings be upon him) both let his hair grow long and shaved it, and he did not say that there was any reward for growing the hair long, nor is there any sin in shaving it, but he commanded men to take care of their hair. It was narrated from Abu Hurayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: “Whoever has hair, let him take care of it.” It was narrated that ‘A’ishah (may Allah be pleased with her) said: I used to comb the hair of the Messenger of Allah (peace and blessings be upon him) when I was menstruating.

Having stated the above, it becomes clear that there is nothing wrong for a Muslim male to shave his head other than for Hajj and in the case he let his hair grow, he has to take care of it.

As for women, according to Islam, there is nothing wrong in women having their hair shortened as long as it is done for the sake of beautifying themselves for their husbands and nothing
more. This is quite different from shaving head, which is completely forbidden for women.
If a woman has her hair cropped with the intention of looking masculine or non-Muslims, then it is forbidden, because the Prophet, peace and blessings be upon him, is reported to have said: “May Allah’s Curse be inflicted upon women who imitate men and vice versa.” (Reported by Al-Bukhari and Muslim)