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.
Navigate to your Phone app located at the bottom of your iPhone home screen. Tap-open the Phone app. Once you have done that, you will see a voicemail logo the bottom right corner of the window that has opened, select that voicemail icon. That action will open the visual voicemail interface. At first, all you will see is a blank screen with a

You don't need an app to record your calls with the 3-way calling described above. There are several paid services that let you call them direct to get the recording going before you pull in the other party. This also means you're not limited to iPhone only—they'll work with an Android phone, or even a landline.
If a phone rings once and then goes to voicemail or rings only briefly, it usually means either that your call is blocked or that the phone is not receiving calls at all. If the phone rings five times and then voicemail picks up, it's more likely that the person on the other end simply isn't picking up the call.