The afterlife is a term referring to a person's continual existence after death.
The Bajorans believed that after death they would join with the Prophets in the Celestial Temple.
Some Humans believed that depending on ones actions during life they could go to different afterlives, the worthy would be ascended to heaven while the rest would fall into the depths of hell.
Klingons had a similar belief with honourable warriors going to Sto-Vo-Kor while the dishonoured went to Gre'thor.
The Ferengi afterlife is based around profit. Successful Ferengi, those who make profits, go to the Divine Treasury. Those who aren't go to the Vault of Eternal Destitution.