Answer:
Hinduism is a religion with various Gods and Goddesses. According to Hinduism, three Gods rule the world. Brahma: the creator; Vishnu: the preserver and Shiva: the destroyer. Lord Vishnu did his job of preserving the world by incarnating himself in different forms at times of crisis.
The three Lords that rule the world have consorts and they are goddesses too. Consort of Brahma is Sarasvati; goddess of learning. Vishnu's consort is Lakshmi; goddess of wealth and prosperity. Shiva's consort is Parvati who is worshipped as Kali or Durga.
Besides these Gods and Goddesses there are a number of other Gods and Goddesses. To name a few of them, there is Ganesh; who has an elephant's head and he is also a son of Shiva and Parvati, Hanuman; who is an ape, Surya; Lord of sun, Ganga Ma; Goddess of river Ganges; Samundra; Lord of the sea, Indra; king of the Gods ( but he isn't an important God), Prithvi; Goddess of earth, Shakti; Goddess of strength. The Hindus call their Goddesses 'Ma' meaning mother.
Some gods have more than one name. Shiva is also known as Shankar, Mahadev, Natraj, Mahesh and many other names. Ganesh is also called Ganpati. God Vishnu incarnated 9 times to do his job and in his every appearance he had a different form which are also worshipped as Gods. Among his appearances, he appeared as Rama, Krishna, Narsimha, Parsuram and Buddha. Krishna also has different names, Gopal; Kishan; Shyam and other names. He also has other titles with meanings like 'Basuri Wala' which means the flute musician and 'Makhan Chor' which means the butter stealer. There are also Gods who can change their forms, for example: Parvati can change into Kali or Durga.
Not all of these Gods are worshiped by all Hindus. Some Hindus worship only Vishnu. Others worship only Shiva. Others worship only the Goddesses and call these Goddesses collectively as Shakti meaning strength. Many of these Goddess worshipers worship Parvati in her images as Kali or Durga. People who worship Shiva or Vishnu also worship characters and images connected with these Gods. Vishnu worshipers (Vaishnaites) also worship his appearances. Shiva's worshipers (Shaivites) also worship images of bull called Nandi, who was Shiva's carrier and a unique stone design connected to Shiva. There are also Hindus who worship all the Gods. There are some Gods who are worshiped all over India like Rama and Krishna and other Gods who are worshiped more in one region than the other like Ganesh who is worshiped mainly in west India. Hindus also worship Gods according to their personal needs. People who engage in wrestling, body building and other physical sports worship Hanuman, who in Hindu legends was an ape with lot of physical strength. Businessmen worship Lakshmi, Goddess of wealth.