“This app requires specific features not available on this device”

[sfphoto]

WhatsApp Messenger
iPad 4 Mini w/ cellular capability (but no sim installed)
iOS12 (App Store page says iOS12 or newer)

 

[DeltaMac]

There is no Whats App app for iPad.

You CAN use What's App in a web page on your iPad, but What's App for iPad (which would be for iPadOS, not just iOS) does not exist (yet).