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?
Just click the "Phone" App from the home screen of iPhone. You can press "1" or the "Voicemail" key to access to voicemail on AT&T phone. Note: T-Mobile users, tap on "Keypad" or press 123. Verizon users, press *86 instead of 1. And Sprint users, press 1. And then you can change the default voicemail on iPhone from different carriers.

When you receive a new voicemail, the Voicemail icon will appear in the notification bar. You can also access your voicemail to check your messages by selecting and holding the One (1) key from the dial pad, follow these steps: From any Home screen, tap Applications. Scroll to and tap Visual Voicemail. Scroll to and tap the voicemail message you want to hear. Tap the blue Play icon to listen to the message.
1. Install the software on a device separate from your phone, like your pc or laptop.