Cause:

The error states that the object which you try to create already exist on the database and so the database is not allowing to create a duplicate object with the same name

SQL> create view test_vu as select * from test;
create view test_vu as select * from test
                                     *
ERROR at line 1:
ORA-00955: name is already used by an existing object

Workaround:

Use different new name for the object

SQL> create view test_vu1 as select * from test;

View created.