Certain Android devices do not come preloaded with the ability to look at the internal storage.
You need to download a File manager app.
Once you have downloaded it, you can see the files you have created in the iReal Pro folder - including exported audio files and recordings.

The file should be saved here:
/storage/emulated/0/Android/data/com.massimobiolcati.irealb/cache

When you quit the app, cache gets cleared so we recommend using a file manager app like Solid Explorer or FX file manager, which supports exporting WAV file.
Both these file managers also appear in the Share window (many do not do this) so you can save to your SD card internal storage.