1. 
-- in initparamter file set
LOG_ARCHIVE_START=TRUE 
LOG_ARCHIVE_DEST=your_destination     
LOG_ARCHIVE_FORMAT=your_format 

2. clean shutdown the database

3.
-- startup using the initparameter file
-- dont disturb the spfile
-- issue 
startup mount pfile='your pfile';
alter database archivelog;
alter database open;
archive log list; 
archive log all; 

if all of the above goes good, it means everything is OK. you can see archived log files in LOG_ARCHIVE_DEST

4.
-- now since everything is ok, you should reflect these
-- changes to the spfile
-- issue
create spfile from pfile;

5.
-- do a clean shutdown
-- issue
startup
-- this will make use of the spfile by default
6.
-- check whether archive log mode is ON
-- issue
archive log list