Assalaamu alaykum. Please, I have a friend who wrote لامساس (i.e. do not touch), which is similar to what was used in Surah Taha (Quran 20: 97). He claimes that he is using it as a protective word so that evil things will not come near him. However, I told him that such word used in the Quran is used to rebuke Musa Samiri, but the guy insisted. So I do not know if it is allowed to use such word for protection in Islam.

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 ʻalayhi wa sallam, is His slave and Messenger. 

It is impermissible for your friend to use this word for the purpose of protection against evil because even if we considered it a Quranic amulet, the preponderant view in this regard is that it is prohibited to use all kinds of amulets given the general indication of the relevant religious texts underlining the prohibition in this regard, and also in order to block the way for any probability of Shirk (polytheism) or of exposing Quranic verses to disrespect.

Nevertheless, there is a difference of opinion among scholars regarding the amulets containing Quranic verses. Some scholars held that it is allowable to use amulets containing Quranic verses and Thikr (remembrance of Allaah). If your friend follows this scholarly view, then you should not forbid him from following it because one should not forbid or criticize those who choose to follow the scholarly view (opposing theirs) when it comes to matters about which there is a difference of opinion among scholars.

For more benefit, please refer to fatwa 84878.

Allaah knows best.