My cellular data is not working, Help me how to resolved this issue

See this Apple article: If you see No Service or Searching on your iPhone or iPad

If you see No Service or Searching on your iPhone or iPad - Apple Support

See these Apple articles below:

How to unlock your iPhone for use with a different carrier

How to unlock your iPhone for use with a different carrier - Apple Support

👉 Apple can't unlock your iPhone for use with a different carrier. Only your carrier can unlock your iPhone.

You need to contact your Carrier.

Manually update your carrier settings on your iPhone or iPad

Manually update your carrier settings on your iPhone or iPad - Apple Support

Update your network provider settings manually on your iPhone or iPad

Update your network provider settings manually on your iPhone or iPad – Apple Support (UK)

If you can't make or receive calls on your iPhone

If you can't make or receive calls on your iPhone - Apple Support

If you can't send or receive messages on your iPhone, iPad, or iPod touch

If you can't send or receive messages on your iPhone, iPad, or iPod touch - Apple Support

If they are On, turn Off Hotspot & VPN.