Depending on the device model, a 2G, 3G or 4G (LTE) network is supported, and a preferred network mode can be selected on the LG device accordingly.

Android 9 (LG UX 9.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Mobile networks
Step 3:  Tap on  Network mode
Step 4:  Choose desired  network mode
  1. Open the Settings
  2. Tap on Mobile networks
  3. Tap on Network mode
  4. Choose desired network mode

LG Instructions