4. How to uninstall the third-party apps pre-installed or installed by the user?

A: Please go to Settings -> General -> Apps, locate and click on the app that you want to uninstall, and then click the 'UNINSTALL' icon. 

Btw, there are four 3rd-party apps preinstalled on the M9, and they are Tidal, MOOV, KKBOX and 网易云音乐(NetEaseCloud).