There are 7 main bodies in the human being: physical (related to matter), etheric (linked to vitality), astral (linked to emotions), mental (related to thought), causal (related to karma), Buddhist (related to supra-mental), atmic (Divine body).
The last two bodies (Buddhist and Atmic) are accessible only by a few exceptional Beings such as Realities. As for the other bodies there are differences.
Indeed, one can naturally work on the first four (physical, etheric, astral and mental) through some more or less known means of all such homeopathy, aromatherapy, Bach flowers, hypnosis, sophrology, magnetism, Qi Gong, etc.
On the other hand, to reach the causal plane, it is necessary to go through the channel of a realized Being. Acting on the causal plane is indispensable because it is at this level that the notion of karma comes into play. It is here that the causes of all effects are born; it is here that all these causes are registered; it is only on this plane that they can be erased. Otherwise, it's like pulling out a weed that would remain a part of root ... The weed will eventually grow back. This is the very principle of the butterfly effect: an effect causes a cause which, in turn, leads to other effects ...