Click on above link to download sample greetings, you can upload it to Voice Menu as shown below.
The Voice Menu is used for implementing an IVR (Interactive Voice Response) or automated attendant system. The Voice Menu plays a recorded or uploaded message, and prompts the caller to enter an extension number. The call is then passed to the connecting object with the matching extension number.
The information to be entered for this object is:
The name of the Voice Menu.
A voice message that may either be recorded directly, or may be uploaded from an existing file. Typically this message would include information pertaining to extension numbers that are to be pressed by the caller in order to connect with people or departments.
In order to record a message, follow the simple instructions shown.
Alternatively, a voice message in .mp3 or .wav format may be uploaded, or use the sample file (spam blocker greeting.mp3 from the above link.