DLL command are loged in separate log files
There are two DDL logs that contain the same information. One is an XML file, and the other is a text file. The DDL log is stored in the log/ddl subdirectory of the ADR home.
http://docs.oracle.com/database/121/REFRN/refrn10302.htm#REFRN10302

Explanation
1. Shut down the database.
2. Restart the database in UPGRADE mode.
3. Change the setting of MAX_STRING_SIZE to EXTENDED.
4. Run the rdbms/admin/utl32k.sql script. You must be connected AS SYSDBA to run the script.
5. Restart the database in NORMAL mode.
References:

Explanation/Reference:
Explanation:
* The CREATE DATABASE ... ENABLE PLUGGABLE DATABASE SQL statement creates a new CDB. If you do not specify the ENABLE PLUGGABLE DATABASE clause, then the newly created database is a non-CDB and can never contain PDBs.
Along with the root (CDB$ROOT), Oracle Database automatically creates a seed PDB (PDB$SEED). The following graphic shows a newly created CDB:

* Creating a PDB
Rather than constructing the data dictionary tables that define an empty PDB from scratch, and then populating its Obj$ and Dependency$ tables, the empty PDB is created when the CDB is created. (Here, we use empty to mean containing no customer-created artifacts.) It is referred to as the seed PDB and has the name PDB$Seed. Every CDB non-negotiably contains a seed PDB; it is non-negotiably always open in read-only mode. This has no conceptual significance; rather, it is just an optimization device. The create PDB operation is implemented as a special case of the clone PDB operation.