The Afterlife, or life after death, is an unconfirmed phenomena in which the conscience exists in another form after the death of the physical body. It forms a core belief in many religions that the experience of the physical body isn't the end, but instead, part of something greater. On Earth, the Human species has many such religions in which life continued on after death (like Christianity, Buddhism etc.)
The lack of a belief in the afterlife is represented by atheism, the opposite of theism.
Types
Heaven & Hell
The idea of heaven and hell is based on the actions of the person who lived; whether they commited good deeds or bad deeds, they would ultimately arrive in Heaven, if they committed mostly good deeds like improving other lives, and Hell if they were intentionally causing harm to other beings. In ancient Earth, around the 21st Century, Christianity represented the largest monotheistic religion on the planet, accounting for 31% of the global population at the time.
Reincarnation
Reincarnation is the belief that consciousness continues on after the death of the physical body. Some religions believe that experience in the physical body is simply one phase of the overall life in the Universe. They may believe that there is a spiritual or higher dimension that transports them into their new bodies after the last one dies.