How can I enable my VoIP iOS app to be selected when trying to make a call from a contact

How can I show my VoIP calling app in the same list as Facetime and Whatsapp as shown in the image?

My app implements VoIP calls and is integrated with CallKit.

Any tip would be appreciated!

How can I enable my VoIP iOS app to be selected when trying to make a call from a contact
 
 
Q