Is it permissible for a virgin girl to write her will or inheritance to one person without her brothers and sisters or her mother?

It is permissible for a girl to bequeath up to one-third of her wealth to someone who is not an heir. Any amount exceeding one-third depends on the approval of the heirs, based on the Prophet's (peace be upon him) saying: "The third, and the third is much," and his saying: "Indeed, Allah has bestowed upon you one-third of your wealth [to dispose of] at your death."

As for a bequest to an heir, it is not executed unless the remaining heirs consent to and approve it, based on the Prophet's (peace be upon him) saying: "There is no bequest for an heir unless the heirs wish it."