You might feel be annoyed when the iPhone 6S shows the icon of that audio app often played by you whenever you make make hands-free on the device. That is because the iPhone does record the audio you seem to play often. It turn to awesome on users who feel convenient because they actually can access directly the app from the Locked screen. However, if you want to get rid of this, you can quickly Turn Off Suggested Audio App on iPhone 6S Lock Screen in seconds.
How to Disable Suggested Audio App on iPhone 6S Lock Screen
From Settings on iPhone 6S → Tap App and iTunes Stores.
And then you are able to see SUGGESTED APPS below Use Cellular Data option. Just set Installed Apps to OFF.