So since it came up recently decided to type up some general information on this since the only exposer a lot of people who’s beginning is rooted in western culture end up hearing about one of these and the monotheistic versions are generally the first thing that comes to mind.
A simple explanation is it is a form of alchemical or ritual rite with specific aims in mind carried out by aligning with a specific spiritual being or force to expand the aspect of this within your microcosm through resonance to the macrocosmic aspect of said force or being to either bring about a change within self(alchemy) or a change outside of self(sorcery). One does effect the other constantly but the subjective focus of the operator is usually focused more on one or the other as a starting point.
One of the specific versions of this include the following.
From the vedic perspective this is a way to align with the various gods and planets that want to work with you or would be most beneficial to you personally and those that have chosen to act as guides when you came to this plane. The way this is worked out is through a specific type of astrology reading geared to learning what planets want to help you in what ways and then learning which gods connected to those planets best align with you specifically and constructing a mantra for a specific ritual based off your chart to best attune you to those forces and bring about change again either change within self or outside of self.