Recording conversations using the iPhone

[Beverly Wieland]

If I want to record a conversation (such as between myself and my doctor) 
using my iPhone 7, is there a built-in app or should I download one?
If I need to download one, which app would you recommend?
I hope this is not too elementary a question to ask!
But I would really appreciate your advice, and thank you in advance.

Beverly Wieland
bwiel...@udel.edu