According to ''Halakha'' the case should be placed on the right side of the door
(from the point of view of one entering the building or room) on the lower part of the upper third of the doorpost (or around shoulder height for high doorways), within approximately 3 inches of a doorway opening. The case should be permanently affixed with nails, screws, glue, or strong double-sided tape. Great caution should be exerted not to puncture, rip, or crack the parchement or the wording on it which would invalidate the process entirely. Ashkenazi Jews tilt the case indoors (to accommodate the variant opinions of Rashi and Rabbeinu Tam as to whether it should be placed horizontally or vertically) so that the top slants toward the room the door opens into. Other Jews place the case vertically.
The procedure is to hold the ''mezuzah'' against the spot upon which it will be affixed, then recite a blessing, which translates as:
"Blessed are You, Lord our "Names of God in Judaism", King of the Universe, Who sanctified us with His ''mitzvah/mitzvot'', and commanded us to affix a ''mezuzah''".
After the blessing is made, the ''mezuzah'' is attached. When affixing many ''mezuzot'', the blessing is made only before affixing the first ''mezuzah'', while having in mind that that first blessing applies to the affixing of all the other ''mezuzot''.
Observant Jews affix ''mezuzot'' on all the doors of their homes with the exception of bathrooms or very small rooms (''e.g.'', closets). The garage door is not exempt from the mezuzah.
The City Gates of Jerusalem have huge mezuzot that were affixed after the Old City came under Israeli control after the Six-Day War in 1967.
