For extension voicemail, extension users can choose how to play greetings in different presence: Default greeting: Play a greeting for any presence that doesn't have a personal greeting. Presence greetings: Play a personal greeting for each presence (available, away, do not disturb, lunch break, business trip, and off work).
Once you have your message, you need to actually record it. The exact process varies depending on whether you’re using a cell phone or office phone, but here’s the basic process: Press the voicemail button, or press and hold 1 on most cell phones. Enter your password. Record your message. Listen to the message you just recorded. Follow the prompts to save your message. Following Up on Voicemail Messages

Most people screen their phone calls and often avoid answering unknown numbers. If you’re applying for new positions, you should try to view each unexpected call as an exciting opportunity! In the event that you simply can’t pick up the phone, you’ll want a polished voicemail greeting to let the caller know they’ve reached the right person.
A voicemail greeting can be pivotal in attracting a potential customer to your company or repelling him! So, it may be worthwhile to utilize some tried and tested tips to frame voicemail greetings for your company. The first line must include a brief description of your company and the services it offers clearly. Tell the callers the time frame within which they will get a call from your end. Ensure the voice used in recording the greeting is cheerful and not drab one. Ensure the greeting is recorded not in a hurried manner so that the callers can understand each word without issues. Try keeping the voicemail message length to 20 seconds or so.