Al-Jawab Billahi At-Taufeeq (the answer with Allah’s guidance)
Hair extensions is Haraam (forbidden).
Rasulullah (Sallallaahu Alayhi Wasallam) said, Allah curses the Waasilah (person who extends hair) and the Mustawsilah (person who seeks to extend hair).’ (Bukhari)
Narrated Humaid bin ‘Abdur-Rahman:
That he heard Muawiya bin Abi Sufyan (talking) on the pulpit in the year when he performed the Hajj. He took a tuft of hair that was in the hand of an elderly and said, “O people of Medina! Where are your learned men? I heard the Prophet forbidding such a thing as this (i.e. false hair) and he used to say, ‘The Israelis were destroyed when their ladies practiced this habit (of using false hair to lengthen their locks).”
(Bukhari 4:674 see also Bukhari 4:694, 7:816 )
An Ansari woman gave her daughter in marriage and the hair of the latter started falling out. The Ansari women came to the Prophet and mentioned that to him and said, “Her (my daughter’s) husband suggested that I should let her wear false hair.” The Prophet said, “No, (don’t do that) for Allah sends His curses upon such ladies who lengthen their hair artificially.” (Bukhari 7:133 see also Bukhari 7:818 )
Narrated Jabir ibn Adullah:
Allah’s Apostle reprimanded that a woman should add anything to her head (in the form of artificial hair). (Muslim)
And Only Allah Ta’ala Knows Best.
Moulana Qamruz Zaman