Salvation can be defined as freedom of soul from the cycle of birth and rebirth and becoming one with the Supreme Soul. The Sanskrit word for salvation is Moksha or Nirvana. The word Moksha is mainly used by Hindus and the word Nirvana is mainly used by Buddhists, but the meaning is the same.
According to Hinduism, the soul (Atma) dwells in every living being. Death is that of the body and not of the soul as the soul is immortal. When a person dies, the soul enters a new body. Depending upon its Karma in the past life, it gets a new body and undergoes happiness and/or sufferings again. This cycle continues until the soul attains salvation i.e., freedom from the cycle of birth and rebirth.
Attaining salvation is the ultimate goal of a Hindu’s life. In Bhagavad-Gita, Lord Krishna has described many ways to attain salvation. It is important to know that only human beings can get salvation. We get this human body when the soul travels through 8,400,000 species. Hence we should utilize this birth to attain salvation. To attain salvation, we do not need to become ascetic. Though that is a very famous way, it is not possible for everybody to denounce the normal life and become an ascetic.
Dharma, Artha, Kama, and Moksha are the four aims of a human life amongst which Moksha is the final aim. After fulfilling all our duties towards society and family, we should turn our attention towards Moksha. All our actions should be done as duties within the frame of the rules of society and we should devote all our actions to God.
As mentioned above, our soul travels through 8,400,000 species to get the human body. After that, it travels through many human bodies to gain Nirvana. The soul is always learning in these births and advances itself towards its ultimate aim. Many human births are required to attain Nirvana, in general. It is better that we start our journey towards it as early as possible. The efforts you put towards it never go in vain. If you cannot attain salvation in this life, you would get the benefits of your efforts in the next life and you would advance more in the next life.