Thank you for reaching out 昭如,
It sounds like you're trying to port your phone number to a new cellular provider. We can help.
When it comes to porting your number, you will want to make sure your device is not locked to the original carrier, and then contact the new carrier and have them submit the request on your behalf.
You can follow these steps to Set up cellular service on iPhone. In particular, these sections may be helpful:
Some carriers support transferring a phone number from your previous iPhone to your new iPhone [eSIM] without needing to contact them. Make sure you’re signed in with your Apple ID on both devices, or make sure your previous iPhone is unlocked, nearby with Bluetooth turned on, and running iOS 16 or later.
Some carriers let you unlock iPhone for use with another carrier (additional fees may apply). Contact your carrier for authorization and setup information. See the Apple Support article How to unlock your iPhone for use with a different carrier.
Hope that helps.
Take care.