Apple iPad cannot make or receive phone calls and text messages whether it is WIFI only or WIFI+ cellular.
You can only make/receive phone calls and text messages through Facetime and iMessage( which is for Apple to Apple devices only and requires internet connection) .
The purpose of having cellular is for the sim card slot for your iPad to connect to internet if no wifi connection is available. Don’t confuse yourselves
So be carefull before purchase. I’m happy to say that Don’t purchase it because Apple is going to half the rate of its tab at the end of the march month:)