How do I make calls and text messages on my iPad

An iPad, whether a Cellular model or not, is not capable of accessing Cellular Voice or Messaging features. An iPad with Cellular connectivity alone can only access IP-data services.

If paired with an iPhone, the capabilities of iPad significantly broaden to include Cellular Voice and Messaging services of the iPhone - relayed to the iPad over WiFi using Apple’s continuity features.

Continuity

https://support.apple.com/en-gb/HT204681

SMS/MMS Messaging

https://support.apple.com/en-us/HT208386

WiFi Calling

https://support.apple.com/en-gb/HT203032

I hope this is helpful in clarifying your iPads Calling and Messaging features.

See these support articles:--> Make and receive calls on your Mac, iPad or iPod touch – Apple Support

and/or this one:--> Send and receive text messages on iPad - Apple Support

Regards

Giulio