You can share your 3G connection by turning it into a WiFi hotspot for your friends to use together.
Here's how to share your 3G connection as WiFi on Asus Zenfone 4 Max ZC520KL:
Step 1: Go to settings and select Additional Settings.
Step 2: Select USB Internet & Mobile Access Point.
Choose mobile access point
Step 3: Activate the feature.
Activate the feature
Step 4: You can adjust the shared network configuration.
Adjust network configuration
That completes the setup. Wishing you all success!