By phone-app,  I assume you are talking about the dialler for making calls.  The bundle ID for such apps can differ in different phone brands and models, as most phone manufacturers use customized version of dialler optimized for their phones rather than the default dialler from Google's Android original source code base.

Unfortunately, you've not stated your phone models.   I haven't tested any Motorola Android phone in details in the last few years and cannot guess what you can try.   However, for many recent Samsung phone models, the default dialler apps bundled with the phones can be initiated in MobiControl kiosk mode (locddown menu) with

  Launch://com.android.contacts/com.android.dialer.DialtactsActivity

, which provides access to the dialler as well as the contact book. 

Good luck!

Hi Raymond, The devices on which i tried are Samsung J400F, Samsung Galaxy Tab A, Samsung Galaxy J7 Pro through Android+. And on Motorola G5 Plus and Motorola E5.