How do I lock my iPhone 12 that was done by Verizon wireless
How to unlock my iPhone 12 mini that was not allowed or given the option to be unlocked saying contact cell phone carrier?
Only the cellular carrier (in this case Verizon) whom that iPhone is locked to can unlock it, if you're eligible.
See also this support article:--> How to unlock your iPhone for use with a different carrier - Apple Support
Regards
Giulio