On the app, click on the "Sound" icon at the lower left part of the tool and select "Microphone." Then, open your voicemail service on your phone and play the voice message. The online audio recorder then clicks the "Record" button on the audio recorder while the voicemail is playing. If you are recording using an external mic, make sure that your phone is on the loudspeaker and pointed at the mic.
When you're in a call, wait for the Add Call button to light up, so you can add a third caller via 3-way calling. Tell the other person to wait, click the button, and call yourself. Stay on the line and listen to your own voice mail greeting, then for the tone that indicates recording has begun. Tap Merge Calls. All three calls are merged—and the third one (your voice mail) is taping the other two.

An excellent business voicemail greeting conveys your level of professionalism and competence while also providing your callers with a glimpse into your company’s culture and level of care. As minor as it may seem, your voicemail greeting can instill confidence and trust in your callers or it can be a cause for concern.
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.