Folders are sections in your mailbox that help you manage your emails better. In your Rediffmail, you shall find folders like
‘Inbox’ – where all the mails are stored.
’Junk Mail’ – where all the bilk mail/junk mail arrives.
’Deleted Mail’ - where all the deleted mails arrive.
‘Sent mail’ - where all the sent mails are stored (if option chosen).
’Drafts’ - where all the unsent mails are stored.
You can also create your own folders to store your incoming mails. Eg: Friends, Work, Family etc.