Create a database and user according to the following document.
Create Tablespaces and Database on Oracle
The database needs to be in open read-write access.
ORA-16000:database open for read-only access
Cause: The database has been opened for read-only access. Attempts to modify the database using inappropriate DML or DDL statements generate this error.
Action: In order to modify the database, it must first be shut down and re-opened for read-write access.