Brahma – the creator (in charge of raja-guna – the quality of passion).
Vishnu – the maintainer On charge of sattva-guna – the quality of goodness).
Shiva – the destroyer (in charge of tama-guna – the quality of ignorance).
In the material world there are three principal deities called the trimurti (literally "three deities").They correspond to God's functions of creation, sustenance and destruction (see also Prakriti and Guna).
God also exists beyond this world, as an impersonal force and/or as the Supreme Person. Most commonly that transcendent Supreme is identified with Vishnu, or one of his forms (such as Krishna, Rama, or Narayana).
Brahma,
the creator (or secondary creator, since he is born of Vishnu, the original
creator). Direct worship of Brahma is rare, and in India there is only one
major temple dedicated to him in Pushkar, Rajasthan. Some consider him to
be worshipped indirectly through the chanting of the Gayatri mantra, since
Gayatri is one of his consorts.
Vishnu, all-pervading yet also a person. He is most often worshipped in his forms as Krishna and Rama (see Twelve Principal Deities).
Shiva, with his carrier, Nandi the bull. Shiva is in charge of universal destruction, though he also has a role in creation. He represents the male principle within this world, while his female counterpart, Shakti, is his consort and the personification of material energy (Mother Nature).
Common Misunderstandings
The Trimurti is the Hindu Trinity
The implied comparison here with Christianity is potentially misleading, and hence the term "Hindu Trinity" is best avoided.