$ sudo apt-get update
$ sudo apt-get install cyrus-imapd 

cyrus-imapd is installed in your system.

Make ensure the cyrus-imapd package were installed using the commands given below,

$ sudo dpkg-query -l | grep cyrus-imapd *

You will get with cyrus-imapd package name, version, architecture and description in a table

cyrus-imapd package basic information: