Can I upgrade my iPad 10th Gen to Cellular?

Sorry no.

The iPad hardware differs between the "Wifi" model and the "Wifi + Cellular" model. In fact, the second model in addition to the data network, also has GPS, and it is not possible to modify what you have purchased.

You will have to try to resell (or exchange) the "Wifi" model for the "Wifi + Cellular" model.

Regards

Giulio

WiFi Only models if iPad do not have any Cellular capabilities - and hardware cannot be retrofitted.

Whilst a WiFi Only iPad cannot be transformed into a WiFi+Cellular model, you can 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