What is magnetic Terapy already?

Answer 1

Largely placebo.

Answer 2

Terapy - I looked up that word in a few dictionaries and couldn't find an English definition.

If you mean "therapy", magnetic therapy is based on the idea that the human body has an electromagnetic field that can be manipulated or influenced by outside magnetic fields (such as in a magnetized bracelet).
Some people claim that magnetic therapy has helped with chronic problems, but there is no scientific evidence to support the claims made.

But if it helps someone with pain or other chronic problems, then it doesn't really matter much if the relief is real or imagined.