Physically, if open the kickstand, you'll see a panel with a tiny hole in it. On all Pro 8 models, this is where the NVMe drive is; on LTE capable models, there will be a slot for a physical SIM there.
Through software, if you click the WiFi/Sound/Battery control on the Taskbar, there will be a control to manage Cellular settings there whether you have a service connected via SIM/eSIM or not at all.
Barb is correct in that only Business models will have LTE; if you have Home installed, it is consumer and will not have LTE.