Offer other contact information such as a cell phone or email address if you will check it (i.e. on vacation). DON’T: Be too informal, even if you are creating a humorous message. Give a prolonged sales pitch in your voicemail greeting message. Waste a caller’s time with an excessively long greeting before they can leave their message.
Most phones don’t make that as easy as it ought to be. Apple’s iPhone will back up voicemails to your computer along with everything else, but they’re stored in a funky file format that’s not easily played by most software. Most Android phones, meanwhile, store your voicemails on off-site servers.

To set up voice mail, tap the Phone icon, tap the Voicemail icon and then "Greeting.". There are two options available: Default and Custom. If voice mail hasn't been set up previously on your phone, Default is selected, which means people will hear your wireless carrier's generic voice mail greeting when they call you.
I have a confession to make: I haven't recorded a new voicemail greeting in nearly a decade. Since then, I've (hopefully) become more articulate, poised, and self-assured. But hear my voicemail recording, and you'd think I was still new to the work world, a little unsure of myself — and probably not an authority.