How to disable ArchiveLog mode in oracle database?

To disable the archivelog mode the database should be in mount state.

Here is the the step by step scripts to disable archivelog mode on oracle database 12c , single instance.

SQL> conn sys/orcl@to_primary as sysdba
ORACLE instance started.
 Total System Global Area 2499805184 bytes
Fixed Size                  8749920 bytes
Variable Size             687869088 bytes
Database Buffers         1795162112 bytes
Redo Buffers                8024064 bytes
Database mounted.
Database opened.

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     3
Next log sequence to archive   5
Current log sequence           5

----shutdown the database 
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.

--- Startup mount 
SQL> startup mount;
ORACLE instance started.
 Total System Global Area 2499805184 bytes
Fixed Size                  8749920 bytes
Variable Size             687869088 bytes
Database Buffers         1795162112 bytes
Redo Buffers                8024064 bytes
Database mounted.
 --- Check the database for Archive mode status
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     3
Next log sequence to archive   5
Current log sequence           5

---- Disable archivelog mode
SQL> alter database noarchivelog;
 Database altered.
 ---- Open the database
SQL> alter database open;
 Database altered.
SQL>