Step 1: First your system and Mobile should be on same WiFi network.
Step 2: Run your React Application with "npm start HOST=0.0.0.0" instead of "npm start"
Step 3: Open your another terminal and get the your system IP address. for that you need to run "ifconfig" command in your terminal.
Step 4: Open your mobile browser, and type "192.168.225.99:3000" in your address bar.This is for Linux Users. [![enter image description here][1]][1]