You can record custom messages right from your dashboard using Dial-and-Record, which allows you to record it through your phone. Then, once they’ve been recorded, they’re saved in your account to be placed in any section, such as for the welcome greeting, menu prompt, or voicemail greeting, in addition to other sections. Enter the number of rings between 0 and 9, or press #. If you choose 0, calls will go straight to your voicemail without ringing first. If you choose # calls won't go to voicemail at all. The phone will ring until you answer or the caller hangs up. Follow the voice prompts.
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?

Website: https://www.indeed.com/career-advice/career-development/professional-voicemail-greeting
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.