I know might this is very common question for you all.
Can Cisco Unity Express send voicemail to an email address? If yes, any additional software license required for the same?
Could you plesae provide me the steps how to implement.
There is no extra license needed to support the email notification feature. There are two method available in CUE, IMAP or standard email notification.
With IMAP, the if the user deletes the email in their inbox, it will get deleted in their voicemail box. With standard email notification, no action taken by the user in with email will translate to their voicemail.
Below are the links to the admin guide mentioned by Paolo.