Unfortunately, there’s no built-in button in your iPhone’s phone app for recording calls. Instead, you’ll have to use a third-party app or service or use a clever workaround.
The Best Professional Voicemail GreetingsCheck out our tips on making sure your voicemail is ready for your next missed call!

Android phones can access voicemail by holding down the 1 key on the dial pad until the phone dials your 10-digit phone number. You will automatically connect to your mailbox and be prompted to enter your temporary password; this password is the last 4 digits of your phone number followed by the # key. Start the Google Voice app. Tap the three horizontal lines at the top left of the screen (sometimes called a hamburger menu), and then tap “Settings.” In the Voicemail section, tap “Voicemail greeting.” Tap “Record a greeting.” How do I access my voicemail? To call your voicemail on an Android phone, simply open your phone’s dial pad and hold your finger down on the “1” key. You can also call your voicemail from a different phone by calling your own number and tapping the pound key. How do you check your voicemail?
All that being said, as voicemail is still thing, and carriers do offer it with every account, iPhones support voicemail. Here’s what you need to know if you want to set it up.