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.
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Step 2: Select USB Internet & Mobile Access Point.
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Choose mobile access point
Step 3: Activate the feature.
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Activate the feature
Step 4: You can adjust the shared network configuration.
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Adjust network configuration
That completes the setup. Wishing you all success!