Backup all archivelogs known to controlfile

backup archivelog all;

Backup all archivelogs known to controlfile and delete them once backed up

backup archivelog all delete input ;

Backup archivlogs known to controlfile and the logs which haven’t backed up once also

backup archivelog all not backed up 1 times;

Backup of archivelog between sequence number

RMAN> backup format 'C:\archive\%d_%s_%p_%c_%t.arc.bkp'
archivelog from sequence 1000 until sequence 1050;