How to enable READ ONLY WITH APPLY mode on data guard?

SQL> startup mount;
ORACLE instance started.

Total System Global Area 1761604576 bytes
Fixed Size                  8897504 bytes
Variable Size             419430400 bytes
Database Buffers         1325400064 bytes
Redo Buffers                7876608 bytes
Database mounted.
SQL> ALTER DATABASE CONVERT TO PHYSICAL STANDBY;

Database altered.

SQL> SELECT database_role FROM v$database;

DATABASE_ROLE
----------------
PHYSICAL STANDBY

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;

Database altered.

SQL> select name, open_mode from v$database;

NAME      OPEN_MODE
--------- --------------------
O19C2     MOUNTED

SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-10456: cannot open standby database; media recovery session may be in
progress


SQL> alter database recover managed standby database cancel;

Database altered.

SQL> alter database open;

Database altered.

SQL> select name, open_mode from v$database;

NAME      OPEN_MODE
--------- --------------------
O19C2     READ ONLY

SQL> alter database recover managed standby database using current logfile disconnect;

Database altered.

SQL> select name, open_mode from v$database;

NAME      OPEN_MODE
--------- --------------------
O19C2     READ ONLY WITH APPLY

SQL>