To pick the check box next to ‘Mark Default Greeting,’ tap the check box to the right of the check box.
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?

You can change the global voicemail greetings for all the extension users or change voicemail greeting for a specific extension. A quick start guide for the administrator who is new to Yeastar S-Series VoIP PBX.
5. Using Visual Voicemail: Access your voicemails. As long as your carrier supports visual voicemail, you can access your voicemails by tapping the Voicemail button in the bottom right corner of the Phone app's screen.