If you’ve already created a custom voicemail on your iPhone, you can tap Play to see how your voicemail sounds. If you’re interested in creating a new message, tap the Custom button. From here, you can start recording your message by tapping Record and tapping Stop whenever you’re finished. Once you’re finished recording, tap on Play to make sure the message comes across as you’d like and hit Save (in the upper right) to save it as your voicemail.
Recording voicemail greetings for your business or personal life requires a separate list of priorities, because they are being used for two distinct purposes and will be heard by two very different types of callers. I have a friend with two cell phones - one for work, and one for personal calls - and if you call both lines, you would never know it's the same person.

When on vacation, provide your callers with a return date and a back-up contact person to accommodate emergencies. This prevents you from potentially damaging a valued relationship while you enjoy some time off.
While this app has the exact same name as the iOS app we listed above, it’s made by a completely different developer. This version includes customizable skins and the ability to record calls or notes as MP3s. Instead of having to tap a button, you can also simply shake your phone to instantly start recording a call. You can also choose to sync your stored calls with Dropbox and select particular contacts whose calls you always want to record (and store).