With Apple Visual Voicemail, the red circle on the phone icon on the main menu changes to an indication of how many new voicemail messages you have received and how many calls you have missed.
There is no definitive answer here, but you should include one of the two at the beginning of your message based on what makes the most sense.

Voicemails don’t necessarily have to be monotonous or extremely jazzy or funky. What you should be looking for is a balance between the two. Whenever you call someone and their voicemail greeting is playing, it tells you a lot about who they are, as a person. Which is why, you’ve got to put a little bit of “you” when it comes to voicemail. And the best part about all of this is, since you couldn’t come to the phone, at least the callers are having a good time listening to the message.
1 hours agoThe original iPhone promised us visual voicemail in 2007. I was blown away by it. Finally, here was a way to see all voicemail messages in a list (like incoming emails) and be able to tap on them to hear them. Unfortunately, even 10 years after the launch of the iPhone, this feature is still not available on all networks, including Three in the UK.