If I'm adding a codicil to my Will, does it have to be notarized?

No, in fact in Arizona, a type-written will does not need to be notarized, it just needs to be witnessed by two people.  Likewise the testator's signature on the type-written codicil need only be witnessed by two people. Arizona also recognizes holographic wills and codicils -- which are handwritten and need not even be witnessed.