Hello;
I need to move the files instead of deleting them in the below command, what should I change to be able to move them for the directory FTP (the files that are more than 21 days old and existed in the directory MP3, I need to move it for directory FTP), what I have to change:
24 0 * * * /usr/bin/find /var/spool/asterisk/monitorDONE/MP3 -maxdepth 2 -type f -mtime +21 -print | xargs rm -f
Regards
Bilal
Try
/usr/bin/find /var/spool/asterisk/monitorDONE/MP3 -maxdepth 2 -type f -mtime +21 -exec mv '{}' ABSOLUTE/PATH/TO/FTP/ \;
PS1
This should better have gone into the Development > Programming/Scripting subforum. That is were the programming and scripting gurus are lurking 
PS2
Please use CODE tags around computer texts (like your crontab entry). It is the # button in the tool bar of the post editor.
PS3
In general it is preferable (IMHO) to simply call a script from the crontab. And then have a script (even if it is only one line like yours) in a file in e.g. your $HOME/bin). Much easier to edit and test then changing your crontab all the time.