A local role exists only in a single pluggable database (PDB), just as a role in a non-CDB exists only in the non-CDB. A local role can only contain roles and privileges that apply within the container in which the role exists.
PDBs in the same multitenant container database (CDB) may contain local roles with the same name. For example, the user-created role pdbadmin may exist in both the hrpdb and salespdb PDBs. These roles are completely independent of each other, just as they would be in separate non-CDBs.
A local role created using Oracle Enterprise Manager Database Express (EM Express) must be created in the PDB where it will be used.
See Also:
Oracle Database Security Guide to learn how to manage local roles