The Egyptians are known to have the first form of writing called hieroglyphics. Not only did the writing consist of various pictures (which would be very difficult for someone like me who can't draw well), they "wrote" on stone. It would take weeks to complete a message. Not only was the process slow, it produced a very large, heavy missive that had to be stored and/or transported.
The Sumerians also had a style of writing that is considered one of the first to be used - cuneiform. It was a series of dashes, lines, and triangles that stood for various letters. The cuneiform was a little bit easier to do because it was written on a clay tablet. If you messed up, it would be a lot easier to fix it. After the writing was complete, the tablet was baked until it was hard.
Both of the above forms of writing have been preserved largely in effect because of what they were written on. We have hieroglyphic writing that can be studied left from the Egyptians because stone (when protected from the elements) will last for a long time. The same goes with the cuneiform. Stone and hardened clay stand a better chance of lasting through rain, fire, etc. Archeologists and historians can use these preserved writings to learn about the life of ancient people.
Later, the Egyptians came up with a form of paper called papyrus. It was made of smashed reeds. This papyrus was much more conducive to sending messages and recording the history of the people. However, while the Pharaohs were very interested in passing down all that they had done from generation to generation, the papyrus, unlike stone, did not last as long. Many of the writings from the time they started using papyrus have been destroyed. So, we do not have as much written evidence of the life of the Egyptians once the papyrus was used.
Anyway, that is just a brief history of what we have been studying. We had a lot of fun learning about the first writings. We wrote our names in hieroglyphics, and I had the kids write a message in cuneiform to one another. They had to decipher what the other said and respond. We also got out the play dough and practiced writing our names in cuneiform on our clay tablets.