So Apple started rolling out the iOS 12.1 update with support for Dual SIM for the iPhone XS, XS Max, and the iPhone XR. The help guide for setting up Dual SIM on iPhone XS mentions that you need to go to Settings » Cellular and tap Add Cellular Plan to add an eSIM to your iPhone. But you can’t find the Cellular option, eh?
Well, you need to go to Settings » Mobile Data and tap Add Data Plan to add an eSIM to your new iPhone on iOS 12.1. The Cellular / Mobile Data options are one and the same. It depends on your carrier. Most carriers in India uses Mobile Data option settings instead of Cellular.
Also, it’s not a new feature or a change introduced with iOS 12.1. Carriers have been displaying Mobile Data option instead of Cellular under Settings for quite some time on iPhone.