my i phone says Locked Sim

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

If you can't activate your iPhone

If you can't activate your iPhone or iPad (Wi-Fi + Cellular) - Apple Support

If you see 'invalid SIM' or 'no SIM' on your iPhone or iPad

If you see 'invalid SIM' or 'no SIM' on your iPhone or iPad - Apple Support

If you need the PUK code, see this Apple article: Use a SIM PIN for your iPhone or iPad

Use a SIM PIN for your iPhone or iPad - Apple Support

You need to have a good Service 

If they are On, turn Off Hotspot & VPN.