Because the afterlife was one of the most important facts in Egyptian life, privation of the remains of the dead was considered a sacred art. If the bodies were not properly mummified, it was believed that soul of the person could not enter the afterlife, and would wonder aimlessly for all time.
The earliest ancients Egyptians burned their dead in small pits in the desert. The heat and dryness of the sand dehydrated the bodies quickly, creating lifelike the natural “mummies”. After they realized that their mummification was working right they deiced to make mummies intentionally. Later, the ancient Egyptians began burying their dead in coffins to protect them from wild animals in the desert. However, they realized that bodies placed in coffins decayed when they were exposed to the hot dry sand of the desert. Over many centuries, the ancient Egyptians developed a method of preserving bodies so they would remain lifelike. They would cut slits into their face and stuff it with sawdust. So, the face would not sink into the sockets. The process included embalming the bodies and wrapping them in strips of linen and covered with resin (water proof) buyer to prevent moisture from entering the mummy. Today we call this process mummification.
They did lots of weird things with the bodies. This is what they do with all the body parts. Arms, Legs they put padding on them. Brain was removed. The head was filled with sawdust. The eyes were pushed back and patched. So, they would look more realistic. Finger nails, and toe nails were tied to the body so they would not fall off. The heart was placed in a canopic jar. A canopic jar was a jar that was ment for body parts to go in. Kidneys were usually not removed. Liver was placed in a canopic jar. The lungs were too. The mouth was lined with wax. The Nostrils were often plugged. The skin was dry so the rubbed moisturizers on it. And the stomach was placed in a canopic jar. Those are what the body organs were done with. That is about Mummification.