How To Do It With Root Access -:
1) Firstly Install Es file explorer
2) Open it > Swipe from left to right > Enable root explorer Grant super SU permission.
3) Go to /data/data/com.whatsapp
Find a folder named as shared_preps and look for the file called com.whatsapp.preference.XML
4) Tap it and open in a text editor.
Find a
Now restart your device and check for WhatsApp calling.
5) Successfully disabled WhatsApp calling.
How To Do It Without Root -:
1) Firstly install Disable Whatsapp Call
2) Open It Normally
3) Now Choose "Mobile" And Tick On Notifications
4) Untick The Incoming Call
5) That's It You Are Done Now.