Sim Carrier Locked

See the following Apple articles:

How to unlock your iPhone for use with a different carrier

https://support.apple.com/en-us/HT201328

See this Apple article: If you can't activate your iPhone

https://support.apple.com/en-us/HT201407

This is a user helping other users with tech questions

forum, you are not addressing apple here  just  fellow users

if it was me then I would contact the carrier it's locked to

and or try reading

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