A Mezuzah is a parchment inscribed by hand with verses from the Torah in Hebrew. It is affixed to the door frames of Jewish homes. In Deuteronomy 6:9, God tells the Jewish people to attach the commandments to the doorposts of their houses. The Mezuzah is the fulfilment of this.
The parchment, written in black ink with a special quill pen, is rolled up and placed in a protective and decorated holder that can be made of any material, and then affixed to the doorways of the house.