iPad Air 4th generation Wi-Fi
Can an iPad 4th generation Wi-Fi only be upgraded later to a Wi-Fi + Cellular by the addition of an eSIM chip, slot, card ot other means?
Question marked as
It is not possible to change or modify the internal hardware components of an iPad.
A WiFi Only iPad cannot be transformed into a WiFi+Cellular model. You can, however, use the hotspot feature of a mobile phone - or a Cellular Broadband Router (often known as a MiFi Router) - to access Cellular networks.
How to set up a Personal Hotspot on your iPhone or iPad – Apple Support