If you create a call answering rule but don't specify an action, your caller will hear the following prompt: "You have reached the mailbox of . Please call back later. Goodbye." and the call will end.
I made this "grouchy voicemail" for whoever is tired of the boring old voicemail your phone service provides. I will have more funny voicemail greetings on

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.
2. After opening Audacity, navigate to Preferences -> Recording, then check “software playthrough.”