Many people prefer to do the sorting/splitting of mail into their mail boxes on the IMAP server. That way they don't have to download the mail they're not all that interested in.
If you do want to do client-side mail splitting, then the following variables are relevant:
nnmail-split-methods(see Splitting Mail), except the symbol
default, which means that it should use the value of the
Here's a complete example
nnimap backend with a client-side
“fancy” splitting method:
(nnimap "imap.example.com" (nnimap-inbox "INBOX") (nnimap-split-methods (| ("MailScanner-SpamCheck" "spam" "spam.detected") (to "firstname.lastname@example.org" "foo") "undecided")))