How to Add Log file in Oracle Database

If you are executing below query you will get the current log file and location below query and sample output
Query:- 
select * from v$logfile;


Output:-
GROUP#,STATUS,TYPE,MEMBER,IS_RECOVERY_DEST_FILE
2,,ONLINE,/testdata/r02/oradata/log02a.dbf,NO
2,,ONLINE,/testdata/r02/oradata/log02b.dbf,NO
1,,ONLINE,/testdata/r03/oradata/log01a.dbf,NO
1,,ONLINE,/testdata/r03/oradata/log01b.dbf,NO

Adding LogFile

ALTER DATABASE ADD LOGFILE MEMBER '/testdata/r03/oradata/log01c.dbf' TO GROUP 1;
ALTER DATABASE ADD LOGFILE MEMBER '/testdata/r03/oradata/log02c.dbf' TO GROUP 2;


GROUP#,STATUS,TYPE,MEMBER,IS_RECOVERY_DEST_FILE

select * from v$logfile;

2,,ONLINE,/testdata/r02/oradata/log02a.dbf,NO
2,,ONLINE,/testdata/r02/oradata/log02b.dbf,NO
1,,ONLINE,/testdata/r03/oradata/log01a.dbf,NO
1,,ONLINE,/testdata/r03/oradata/log01b.dbf,NO
2,,INVALID,/testdata/r02/oradata/log02c.dbf,NO
1,,INVALID,/testdata/r03/oradata/log01c.dbf,NO
Your logfile is added but status is INVALID so please execute below Query

ALTER SYSTEM SWITCH LOGFILE;
ALTER SYSTEM SWITCH LOGFILE;

ALTER SYSTEM CHECKPOINT;

select * from v$logfile;
Output:-
GROUP#,STATUS,TYPE,MEMBER,IS_RECOVERY_DEST_FILE
2,,ONLINE,/testdata/r02/oradata/log02a.dbf,NO
2,,ONLINE,/testdata/r02/oradata/log02b.dbf,NO
1,,ONLINE,/testdata/r03/oradata/log01a.dbf,NO
1,,ONLINE,/testdata/r03/oradata/log01b.dbf,NO
2,,ONLINE,/testdata/r02/oradata/log02c.dbf,NO
1,,ONLINE,/testdata/r03/oradata/log01c.dbf,NO