Writing began long ago and the first written words were pictures. A picture of a cow was also the word for a cow. Only a few scholars in, say, ancient Egypt could do this picture writing and read it and they often carved their words on stone. These early scribes carved records and sacred writings. Our word hieroglyph is coined frcm two older words meaning sacred and carving.
Later, the scribes simplified their picture writing to make phonetic words. The picture of a hawk, for example, was meant for the sound of the vowel A, This idea was simplified again and again until the ancient hieroglyphs became the streamlined letters of our alphabet.