What is the IBAN for Wells Fargo Bank?

Peter Bruins very accurately has answered this question. Just to add to it. US Banks (i.e. Banks IN the United States) do not use IBANs.

The American equivalent is the Bank Account Number and the ABA# (commonly called the Routing number).

US Banks that are chartered outside the US, may issue IBANs in the respective countries they would be working out of.