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.
You have reached our general company mailbox. No one is available to take your call at the moment, but please leave your name, telephone number, and a brief message, and someone will return your call as soon as possible. Thank you and have a great day.

For example, an extension user has different greetings for Lunch Break status and Away status. Lunch Break: "I’m currently on a lunch and unable to take your call". Away: "I’m currently away from my desk".
However, Hinze says that the way businesses use voicemail has changed radically. What once meant a constantly clogged answering machine is now a service that almost always involves the incorporation of more modern functions like automated message transcription. For customers picking up a phone after your normal hours of operation, rather than going to your website, voicemail greetings can keep them apprised of business hours, brief company news items and other critical information.