Death didn't just started happening in this world, but it started when man separates itself from God. Since then, all people experience death because it is part of the fallen condition of the world. The Bible teaches that human life on earth is temporary and that every person will eventually face death.
God did not tell us that after we die that's the end of everything. It teaches that God has provided the hope of eternal life through Jesus Christ. For believers, death is viewed as a passage from earthly life to the promise of being with God, giving hope beyond the reality of physical death.