I have an address that is going to be displayed on a webpage, but it is not the address for the author of the page. How should this be coded to be semantic given the w3c rec
You can use the Schema.org vocabulary's PostalAddress item for this. It can be used via Microdata, RDFa, or JSON-LD.
For example, using RDFa:
Google Inc.
P.O. Box1234
Mountain View,
CA
94043
United States
AFAIK, this should also be valid with in place of the enclosing
Google Inc.
P.O. Box1234
Mountain View,
CA
94043
United States