Check if the iPhone still under warranty

From apple’s website :

Learn more about your service options

Apple provides different options when products need service, including carry-in, mail-in, and do-it-yourself parts service. Availability depends on the product and the country or region in which service is requested.

• You can go directly to our Check Coverage page. Enter your serial number to see the available service options.
• Find manuals, downloads, troubleshooting advice, and more at Apple Support.

Check the serial number here: Check Your Service and Support Coverage - Apple Support

I was going to tell you to enter the serial number here: https://checkcoverage.apple.com

But that doesn't appear to be a valid serial number.