This is basics, but i do see few dba not knowing how to check whether Real-Time Apply has been enabled on the standby using views.Normally alert log would give the required information, but if one wants to check using database views then its “v$archive_dest_status”. To start the real time apply (standby redo logfiles are must for it) –
On Physical Standby –

sql> alter database recover managed standby database using current logfile disconnect from session;

On Logical Standby –

sql>alter database start logical standby apply immediate;

Now to check if its enabled use “v$archive_dest_status”
On standby –

SQL> select DEST_ID,dest_name,status,type,srl,recovery_mode from v$archive_dest_status where dest_id=1;
   DEST_ID DEST_NAME                      STATUS    TYPE           SRL RECOVERY_MODE
---------- ------------------------------ --------- -------------- --- -----------------------
         1 LOG_ARCHIVE_DEST_1             VALID     LOCAL          YES  MANAGED REAL TIME APPLY

The dest_id can be changed as per what is set for standby.If its not a real time apply one would see

SQL> select DEST_ID,dest_name,status,type,srl,recovery_mode from v$archive_dest_status where dest_id=1;
   DEST_ID DEST_NAME                      STATUS    TYPE           SRL RECOVERY_MODE
---------- ------------------------------ --------- -------------- --- -----------------------
         1 LOG_ARCHIVE_DEST_1             VALID     LOCAL          NO  MANAGED