My iPhone is showing sim Not supported when i Put in the SIM card

A SIM Not Supported message means that your phone is locked to a carrier, and the SIM is not for the carrier the phone is locked to. You need to contact the carrier the phone is locked to and ask about their unlocking policy. Here’s more information→How to unlock your iPhone for use with a different carrier - Apple Support

I see you posted a duplicate message that was deleted. There’s no point making duplicate posts.

See this for help. How to unlock your iPhone for use with a different carrier - Apple Support