In Oracle 12c trying to create table with columns greater than 4000 New to Oracle and SQL.
I have already followed normal procedure to allow for this size:

startup upgrade
alter system set MAX_STRING_SIZE ='EXTENDED' scope=spfile;
@%ORACLE_HOME%\RDBMS\ADMIN\utl32k.sql
@%ORACLE_HOME%\RDBMS\ADMIN\utlrp.sql
shutdown immediate
startup;


No error messages during sql scripts or startup.
Tried to create table column in user but still getting error below:

SQL&gt; CONN oracle
&lt;password&gt;
SQL&gt; CREATE TABLE UNIVERSITY ( COLLEGE_NAME VARCHAR2(8000));
CREATE TABLE UNIVERSITY ( COLLEGE_NAME VARCHAR2(8000))
                                                *
ERROR at line 1:
ORA-00910: specified length too long for its datatype

SQL&gt; SHOW PARAMETER MAX_STRING_SIZE

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
max_string_size              string     EXTENDED


Please assist me in finding my error.

@Balazs:  I have attempted your commands but receive errors:  

$ sqlplus /nolog

SQL*Plus: Release 12.2.0.1.0 Production on Tue Jun 18 08:21:34 2019

Copyright (c) 1982, 2016, Oracle.  All rights reserved.

SQL&gt; show parameter max_string_size;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
max_string_size                      string      EXTENDED
SQL&gt; create table UNIVERSITY ( COLLEGE_NAME VARCHAR2(8000));
create table UNIVERSITY ( COLLEGE_NAME VARCHAR2(8000))
                                                *
ERROR at line 1:
ORA-00910: specified length too long for its datatype


SQL&gt; CONN sys / as sysdba
Enter password:
Connected.
SQL&gt; SHUTDOWN IMMEDIATE;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL&gt; STARTUP UPGRADE;
ORACLE instance started.

Total System Global Area 5033164800 bytes
Fixed Size                  8803120 bytes
Variable Size            1040190672 bytes
Database Buffers         3976200192 bytes
Redo Buffers                7970816 bytes
Database mounted.
Database opened.
SQL&gt; ALTER SYSTEM SET max_string_size=extended;
ALTER SYSTEM SET max_string_size=extended
*
ERROR at line 1:
ORA-02097: parameter cannot be modified because specified value is invalid
ORA-02095: specified initialization parameter cannot be modified


SQL&gt;


Not sure where I have gone wrong.
Those are not the correct steps to enable the extended data type. You have set max_string_size to EXTENDED in the spfile (scope=spfile) so it had no effect while running the scripts.

Try again.

Non-CDB:

Enabling the New Extended Data Type Capability

CONNNECT SYS / AS SYSDBA
SHUTDOWN IMMEDIATE;
STARTUP UPGRADE;
ALTER SYSTEM SET max_string_size=extended;
START $ORACLE_HOME/rdbms/admin/utl32k.sql
SHUTDOWN IMMEDIATE;
STARTUP;


Or:

MAX_STRING_SIZE