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?
4. Select “Storage” > “Clear cache” then “Clear data.” Confirm to delete everything for both options.

See the overview for more information on these greetings/messages. Call Handling section Greeting & Leave voicemail instruction : You will only see this option if you select Forward to voicemail in your call handling settings and disable the options to Allow callers to reach an operator and Allow caller to check voicemail .
4. Sprint Wireless: Press and hold the “1” button on the dialer screen of your Sprint phone. This command automatically dials into Sprint’s voicemail system.