Hi

An iPad (Pro or not) is not a cellular telephone. No iPad is capable of making cellular calls.

If you have a cellular iPad, it may receive cellular data. Your iPad comes with a SIM, or you may use your own (if it fits). Here's how to set up service.

Set up cellular data service on your Wi-Fi + Cellular model iPad - Apple Support

iPads are data devices and do not connect to the voice channels on any cellular network.

They only make and receive calls and SMS when paired with an iPhone.

Make and receive phone calls on iPad - Apple Support