It is not permissible for a woman to attach other hair to her hair (hair extensions) because of the warning against hair extensions.

Al-Bukhari and Muslim narrated from Ibn ‘Umar (may Allah be pleased with him) that the Messenger of Allah (blessings and peace of Allah be upon him) said: “May Allah curse the one who adds hair extensions and the one who has them added, the one who does tattoos and the one who has them done.”

Muslim narrated that Jabir ibn ‘Abdullah (may Allah be pleased with him) said: The Prophet (blessings and peace of Allah be upon him) forbade women to attach anything to their head.

This is the view of the massive majority of Muslim scholars.

Almighty Allah knows best.