“This conversation may be recorded” is a sentence that is frequently heared when having a phone call with a business. It means that these businesses may be covered in case they want to prove your commitment, but in case you want to get these conversations to do the same in the opposite direction they will hinder it by any means.
The easiest way to get these conversations is if you record them yourself.
There is no default Android app to do taht. This is a list of Android applications that help us to record conversations over the phone.
Smart Call Recorder (SCR), by I.R.P.
Google Voice, by Google
Call Recorder, by Green Apple Studio
It did not work for me on a Honor 10. Phone calls were not registered.
Automatic Call Recorder, by Appliquato
It did not work for me on a Honor 10. Phone calls were identified and registered, but audio was empty, with length 0:00.