How to change the audio input on ipad pro

[dcom]

I have a series of preexisting audio lectures that I need to listen/study from and although there are apps that let you record external audio, I study in the library or late at home and cant play out loud to re-record them. Also, I havent found and app that lets me upload audio files.

So it occur to me that if I could change the audio input so the ipad could listen to its own internal audio (short of speak), then I could listen to the lectures with my headphones on and record the audios over a note in Notability.

Is that even possible on an ipad pro?
I remember doing that several years ago on a macbook ... but cant find a way in the ipad

How can I change the audio input in the ipad pro?

Thanks