How to find and change the default temporary tablespace and default tablespace for a database instance

set lines 200
col description format a50
col property_value format a30
col property_name format a30
SELECT * 
FROM DATABASE_PROPERTIES
WHERE PROPERTY_NAME LIKE '%TABLESPACE%';

To change the default temporary tablespace, use

alter database default temporary tablespace tmp;

To change the default tablespace, use

alter database default tablespace user_data;