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.
The way a woman cuts her hair short when finishing the rituals (of Hajj or ‘Umrah) is to gather all the parts of her hair together, and cut from the ends of the hair the length of a finger tip. Ibn Qudaamah said in his book “Al-Mughni”: Abu Daawood said: I heard Ahmad having been asked whether the woman should cut her hair short from all parts of the head, thereupon he said: "Yes. Let her gather her hair to the front part of the head and then cut from the ends of the hair the length of a finger tip..."
Some jurists are of the opinion that it is sufficient for the woman to cut three hairs, as previously shown in Fataawa 84306, 89523, and 115567. But the first opinion is preferable, and it is easy and feasible.
Allaah Knows best.