A Kosher scroll is hand written by a trained scribe. It is written on Parchment using a quill to form the Torah like letters.
After a Mezuzah is written it needs to be inspected to be sure that all its letters have been formed correctly and entirely.
The Mezuzah is made of 22 Lines & 713 Letters. There are 4649 Laws Governing the writing of each Mezuzah by a trained scribe.