With this method, you don’t need a third-party app. Call the person you want to chat with, then tap the “Add Call” button on your phone’s screen. Dial your own phone number—the one you’re calling from. This will take you to your voicemail. Once your voicemail has started recording, tap the “Merge Calls” button on your screen. Now, you’ll record your phone conversation onto a voicemail message. When you’re done with the call, you can tap the share button to export it to your Mac via Airdrop, to the Voice Memos app, or transfer it via email or text message. The file is recorded as an M4A, so depending on what you want to do with it, you may need to convert it to MP3 before uploading it to other apps.
Are you creating a voicemail greeting for your entire company or team? These business voicemail greetings will do the trick.

To use a different welcome that you have already recorded, or to return to the default greeting, follow these steps: Open the “Google Voice” application on your phone.To access the Settings menu, go to the top left of the screen and select Menu.In the Voicemail section, select Voicemail greeting from the drop-down menu.To make a greeting active, touch More next to the greeting you wish to use, then Set as active. How can I listen to my Voice mail messages?
By default, the telephone number is the one assigned to you by your organization, but it could also be a cell phone number or email address. In that case, voice mail would be played back through your email Inbox.