By presenting a clear, welcoming message containing relevant information about your business, you are showing callers that you value their time. If your recording is vague, confusing, or drags on, customers will lose interest and hang up the phone instead of leaving a voicemail message.
From the Skype for Business desktop app (if you are running Click-2-Run build C2R 8201.1002 or later), select Set Up Voice Mail. Change your Call Answering Rules You can change what options your callers have when they reach the voicemail service; get disconnected, hear your greeting, record a message, choose to be transferred to the number or user you select. Change your prompt language This is the prompt language that is played to callers. For list of supported languages, see Languages for voicemail greetings and messages from Skype for Business. Configure your Out of Office greeting This is the customized greeting message that is played to callers when your status is Out of Office. This option can be activated "Always," when you have an active "Auto Reply" in Outlook, or whenever you have an out-of-office calendar appointment.  Where you can get your voicemail messages from

Keep it short and sweet so that the caller can quickly leave their message and move on with their day.
2. Company Wide Voicemail Greeting. You want to be a little more formal when you're recording a business voicemail greeting for your company. State your business name, your hours of operation, the manner in which you'll reach out to the caller, and a place where he or she can obtain more information about your business.