FORM_FACOTR

You can use the FORM_FACTOR to determine the device type, however while experimenting this seems to work only in mobile app and not a mobile browser.

To use this module you need to import it like below.

import FORM_FACTOR from '@salesforce/client/formFactor'

The FORM_FACTOR can have below values based on the type of the device.

• Large - If the device is a desktop.
• Medium - If the device is a tablet.
• Small - A phone client

navigator.userAgent 

This seems to work both with mobile apps and the mobile browser. Add the below method to your LWC JS file