When you have new voicemail, the Phone tab in the Skype for Business main window displays the number of your messages. See Contact Card opens the caller's contact card, which lists their phone number, email address, office location, and so on. Open Item in Outlook provides more information about the call.
Greetings can be changed using any telephone, or from the Personal Communications Assistant using a desktop computer; However, departmental mailboxes and those assigned to labs and general spaces must be updated using a telephone.

If you’re less than satisfied in your current phone system voicemail greetings, there is probably a decent reason why. We only employ professional voice talents because we want you provide you a highly effective and high quality recording.
Many busy businesses utilize auto attendant greetings to make a great first impression, however, if your business relies on the personal touch of a live receptionist, it is important to have a plan in place when that position is unstaffed. Make sure your voicemail greeting contains the useful information that your receptionist would normally provide. This could include: location & directions, office hours, website URL, or social media info, as well as any pertinent company information.