When you export a recording to another App, upload or “Render file” in the editing screen, you can define a Fade In & Out to use when doing so.

Set the fade length in milliseconds, 0-800 ms. 0 Is Off.

The fade type to use can also be chosen between “Linear”, “Log” and “dB Log”(linear in dB).
This fade-type is also used in the editing screen when you choose Fade In or Out manually.