All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
It is lawful to seek protection and cure from magic and evil eye provided the treatment is through Quran and known Thikr (supplication and remembrance of Allah). So, if some unknown amulets are used or if the exorcist asks the person to sacrifice an animal or the like, then it becomes prohibited to accept such treatment, as the person who does it is nothing but a juggler and a magician.
There is no harm for the Muslim who performs Ruqyah to read some Quran on some water or to write it and wipe the writing in some water before giving that water to the sick person. This water can also be poured throughout the house or in some of its corners… etc.
As for hanging amulets, it is forbidden if these amulets contain anything other than the Quran or clear and understandable supplications or Thikr of Allah.
The Prophet said: “Whoever hangs up an amulet is guilty of Shirk.” [Ahmad]
But if these amulets contain only Quran or Thikr, some scholars believe that hanging them is lawful while others believe the opposite.
We think that it is unlawful to hang amulets for the following reasons:
1. Hanging "lawful" amulets might lead to hanging unlawful ones.
2. The prohibition of hanging amulets is general; it did not specify a lawful kind of amulet.
As for your question about black magic, we inform you that magic exists and Islam recognizes its existence.
On the other hand, there is no evidence in the Sharee’ah proving that magic is black or white.
For more benefit on the prohibition of wearing amulets, please refer to Fataawa 262186, 28531, 327718, 327748, 330397, 349045, 387391, 85125, and 91549.
For more benefit on supplications and how to treat magic, please refer to Fataawa 82917, 81559, 82543, 88904, 168607, 84498 and 82918.
Allah knows best.