Go to the song you want to record with;
Tap/Click the Share button (top right);
Tap/Click the Record button
 
 
The Record window appears
- select audio input (Mac only)
- use the slider to find the best input volume level (if it is quite faint, move closer to the mic)
- choose from AAC (small for emailing) or WAV format (high quality for audio editing)
 
Don't forget to plug in your headphones when you're recording.
For USB-C (no headphone socket for a cable) use an audio adapter (higher quality ones should work best).
 
Limitations
  • Bluetooth has latency so the recording feature does not work with Bluetooth headphones.
  • For iOS/Android warning: some screen protectors might cover your microphone resulting in a very low input volume
  • The recording process in iReal Pro is for quick, basic recording with the mic built in to your device/computer. If you use the mic built in to your headphones, you are likely to hear latency in the recording.

Once you have finished recording, you need to save it in order to listen to it or send it.
Select one these options:

- Save the file to Dropbox/Box/Google Drive/(Apple) Files
- Email the song
- Copy/Paste it into Garageband (on iOS only)
 
Android only
The Share sheet window gives you options of where to share/save the recording to.
Save to Drive, Email etc. Some FIle managers* appear in the Share sheet window so you can save to your internal SD card (or elsewhere)
*(Solid Explorer, FX File manager)