IPhone 7 No service Cellular updated failed help me

If you see No Service or Searching on your iPhone or iPad

1. Check your coverage area. Make sure that you're in an area with cellular network coverage. ... 
2. Restart your iPhone or iPad. Restart your device. ... 
3. Check for a Carrier Settings update. ... 
4. Take out the SIM card. ... 
5. Reset your Network Settings. ... 
6. Update your iPhone or iPad. ... 
7. Contact your carrier. ... 
8. Get more help.

If you see No Service or Searching on your iPhone or iPad ...

Few Carrier (Cellular Service Provider) do not provide Carrier Settings in full but they offer APN settings for example

• Google FI which has APN to be entered manually as h2g2
• BSNL in India which provides APN pin to be updated manually as bsnlnet
• MTN Ghana which provides APN pin to be updated manually as internet

Settings > Mobile Data > APN [under Mobile Data APN] enter the APN pin

Use the APN pin based on your carrier. Ask them or google and search.

If you do see the option to enter APN then the only option is give below

Carrier Update (Required): Released by your Cellular Service provider (Carrier Update), affects your Outgoing / Incoming calls, SMS, Data etc..

How to Update Carrier Settings

You can manually check for and install a carrier settings update with these steps: Make sure your device is connected to a Wi-Fi or cellular network. Tap Settings > General > About. If an update is available, you'll see an option to update your carrier settings.

Update your carrier settings on your iPhone or iPad - Apple Support

This https://support.apple.com/iphone-7-no-service