Recording conversations... Hmm.. I have so many questions coming up in my mind but i'll refrain from asking and only say this. Don't.
Anyways, which country are you in? Unlike Pakistan, where most Android phones come handy with this "feature", it's an illegal activity and prohibited in most developed countries (by law, not even allowed in Pakistan) and recording option isn't active/available in the phones. I believe there were some apps which used to record telephonic conversation but with a beep in order for other party to know something is up. Lol. Maybe things have changed but this used to be the case a few years ago.