Writing comes with the Bronze Age circa 4th millennium BCE in Sumeria. The development of Egyptian hieroglyphs is also parallel to that of the Mesopotamian scripts, and not necessarily independent.
The hieroglyphic script is logographic with phonetic adjuncts that include an effective alphabet.
The world's oldest deciphered sentence was found on a seal impression found in the tomb of Seth-Peribsen from the Second Dynasty (28th or 27th century BC). Writing was very important in maintaining the Egyptian empire, and literacy was concentrated among an educated elite of scribes.
Check this user-friendly link to understand the origins of writing.