A separate greeting can be created for after hours, and typically includes additional options for customers, or at minimum, informs them that your office is closed. In these greetings, it’s beneficial to inform your caller of your regular business hours, as well as provide them with a link for technical support, or additional contact method (if applicable).
Link to an existing menu provides the way to associate the menu with an existing menu. Linked menus are mirror images and menu changes reflect in both places. This type of menu is created with the same greeting as the source menu. The difference from the pre-populated is that the modifications made to any of the linked menus will update both menus.

Holidays and After-Hours Messages. Don’t forget to extend that great sound to greetings after hours and in other times of closure like holidays and, if applicable, when foul weather prohibits opening. Certain phone systems have specific, user-friendly capabilities for programming these types of greetings.
If you designate a phone number for anything other than an emergency, then 9 times out of 10 people will call you for piddly little stuff that they could just send to help desk. On the other hand, if there's an emergency then a warm body really needs to answer the phone. At any rate, all voicemail greetings need to be short and to the point.