The basis for all creation, including the physical body, is the group of five elements: earth, water, wind, fire, and space. The well-being of the body and mind can be established by purifying these five elements within the human system. This process also shapes the body into a stepping stone towards one’s ultimate well-being. There is a whole system of yoga called Bhuta Shuddhi, which means “purification of the elements.”
Citing from SB 4.2.32 where it says:
Lord Śiva is described here as bhūta-rāṭ. The ghosts and those who are
situated in the material mode of ignorance are called bhūtas, so
bhūta-rāṭ refers to the leader of the creatures who are in the lowest
standard of the material modes of nature. Another meaning of bhūta is
anyone who has taken birth or anything which is produced, so in that
sense Lord Śiva may be accepted as the father of this material world.
As defined in The Mahabharata, Book 12: Santi Parva: Section CCCXII
The puissant Consciousness created the five Bhutas. These are Earth,
Wind, Space, Water, and Light numbering the fifth.
Chapter Fifteen Maya-Shakti (The Psycho-Physical Aspect of the Universe)
In the four Atmas which are contemplated in the Citkunda in the
Muladhara Cakra, Atma pranarupi represents the vital aspect, Jñanatma
the Intelligence aspect, and Antaratma is that spark of the Paramatma
which inheres in all bodies, and which when spread (Vyapta) appears as
the Bhuta or five forms of sensible matter which go to the making of
the gross body. These are all aspects of the one Paramatma (Jñanarnava
Tantra, Ch. XXI, Vv. 1 -- 9).
As defined in Hymn to Kali: Text: Verse 7
The corpse is Nirguṇa-Brahman. The couch is the support (Ādhāra). On
Nirguṇa-Brahman as Thy Ādhāra. that is established in Thine own state
(Pada) as Nirguṇa-Brahman. Gāyatrī-Tantra says, 'By the word corpse is
indicated Brahman as the dead body (Preta).' Gandharva-Tantra says
Sadāśiva is the couch on which lies the subtle Tripurasundarī.
The Devi Bhagavatam: The Ninth Book: Chapter 34
If anybody sets fire to a city or a village, he will have to live in
Ksuradhâra Kunda for three yugas with his body severed. Then he
becomes a Preta (disembodied spirit) and travels over the whole earth,
being burnt up with fire.
The Devi Bhagavatam: The Fifth Book: Chapter 28
The Vârâhî Devî looking like a female boar, came also, seated on an
elevated seat of departed souls (Preta)
Going by the above analysis we can conclude that "Bhuta" means "living beings", which includes normal human beings as well. But "Preta" particularly means the deceased human beings.