Here I am cloning a local PDB using DBCA, which is a new feature in oracle 18c:

Go to

cd $ORACLE_HOME/bin

Execute the command:

dbca

make sure X-windows is configured: export DISPLAY=PCXXXX:0.0

You can use silent installation:

In Linux:

./dbca -silent -createpluggabledatabase -sourcedb ORACLE -createpdbfrom PDB -pdbName PDB_TEST_CLONE2 -sourcepdb PDB_TEST

In Windows:

dbca -silent -createpluggabledatabase -sourcedb ORACLE -createpdbfrom PDB -pdbName PDB_TEST_CLONE2 -sourcepdb PDB_TEST