Egyptians created mummies because they believed in an Afterlife, life after death. They thought that one would need their body to enter the Afterlife. Only then could the soul enter the Afterlife. It was a big part of their religion.
Pyramids were tombs for pharaohs' bodies. The Egyptians built pyramids to protect the mummies of pharaohs. Inside they put gold and treasure. Also, they put belongings of the pharaoh.
The Egyptians created pyramids using and old ramp system. To move the blocks they used large sledges that could be pushed or pulled. The blocks were made with limestone.