Data Pump export and import operations on PDBs are identical to those on non-CDBs with the exception of how common users are handled. If you have created a common user in a CDB, then a full database or privileged schema export of that user from within any PDB in the CDB results in a standard CREATE USER C##common name DDL statement being performed upon import. The statement will fail because of the common user prefix C## on the user name. The following error message will be returned:
ORA-65094:invalid local user or role name
In the PDB being exported, if you have created local objects in that user's schema and you want to import them, then either make sure a common user of the same name already exists in the target CDB instance or use the Data Pump Import REMAP_SCHEMA parameter on the impdp command, as follows:
REMAP_SCHEMA=C##common name:local user name
Oracle Database Concepts for more information about CDBs
Oracle Database Administrator's Guide for information about using Data Pump to move a non-CDB into a CDB
Oracle Database Security Guide for more information about privileges and roles in CDBs and PDBs
"Network Considerations" for more information about supplying a connect identifier on the command line