From command line if you would like to exclude table , tables or schema following command can be used .
For specific table(s)
expdp system/pass directory=dp_dir dumpfile=sample.dmp exclude=TABLE:\ "IN \(\'TAB1\',\'TAB2\',\'TAB3\'\)\"
For schema(s)
expdp system/pass directory=dp_dir dumpfile=sample.dmp exclude=SCHEMA:\ "IN \(\'SCHEMA_NAME1\',\'SCHEMA_NAME2\'\)\"