The default voicemail greeting on the iPhone plays generic Your call has been forward to an automated voice message system recording. If you use your phone for work, create a personalized greeting that tells people you’re a professional.
3. Enter your Pin Number. You will need to know your pin or passcode in order to check your voicemail. If you don't have this code, you will have to retrieve it from your carrier. You will hear instructions to input your pin. Hit the pound key after you enter your pin. Follow instructions on how to listen to your voicemail. It's usually to push a certain number (like 1). That's all there is to it. You should be able to hear your voicemail messages now.

Recording Phone Calls on an iPhone Without Using Apps This method can be considered as the easiest, fastest, and perhaps “dirtiest” way of recording a phone call from an iPhone. All you basically need to make this work is another device that has a microphone that can record (like a computer, iPad, or a portable recording device).
-Hello. I’m sorry I didn’t answer your call. I’m just waiting for more important people to call. If I hear your message and deem you worthy of the title “important,” I will think about calling you back, but for now. Bye! -Beep-