There are procedures for performing Pooja in Hinduism.
The Universe is connected and interdependent.
Any action performed affect another and there may be certain elements which may not be tolerant of your actions.
There may be elements that would help you in your endeavor.
To prevent the former and facilitate the latter some procedures have been evolved in Hinduism.
While this may not be necessary for daily parayana , it is necessary for Pooja and more so for Tantrik Sadhana.
The places are Head, Lips,Heart,Shoulder blades,Palm and Fingertips and in some cases pit of the stomach and Buttocks.
Some Nyasas.
Mahashodha nyasa where a sadhaka or sadhvika places planets, constellations, sacred sites and other elements of Lalita’s cosmology on her or his body. T
Rishi Nyasa, Kara (hand) Nyasa, Matrika Nyasa and Sadanga Nyasa.
Every mantra has a Rishi or seer who first pronounced the mantra,
Matrika Nyasa is a form where the 50 letters of the Sanskrit alphabet are placed on the body.
Sadanga Nyasa uses bijas connected with long vowels of the Sanskrit alphabet.
Kara Nyasa refers to use of fingers and marking them.
Mudras are special expressions with the fingers.
There is another aspect, Dikbandhana, when the Diretions (Space) are marked to prevent evil influences disturbing one’s concentration.