The information you provide in your business answering machine greeting can vary depending on your specific needs, though some basic information is common. You should indicate the business that has been reached, including a specific name if you have a personal business number or extension. If the message is for general use, you might indicate that you are unavailable, though a message for use after business hours can provide the caller with regular business hours. You should not, however, use any language that could be taken to indicate that you are busy with a task that is more important than your caller.
In all there is plenty to consider when you’re recording an answering machine greeting. If you’re aiming toward a more secure home, you can use a very basic message. If you are really funny, and friends and family mostly use the phone line, maybe funny is the best way to go. For businesses, stick with the bare facts that give enough information to callers about when their call is likely to be returned or when they should call again. Tricia Christensen

Voice Prompts – usually combined with a Business Intro announcement, used for Auto Attendant and IVR prompts to provide menu options and assist in telephone navigation.
iPhone users have another option: You can send a voice message from Apple's Messages by tapping the microphone button inside the text box (this works only when you're messaging other iPhones). By default, these voice messages last for only two minutes before they are deleted, but you can change that. Either tap Keep under any sent voice message or go to Settings > Messages and tap Expire under Audio Messages. You can set the expiration date to Never, but this affects only your record of the conversation, not the recipient's.