How do I transfer my phone number to my new iPhone?
If you're switching to iPhone (from an Android phone, for example), contact your carrier to transfer your phone number to your iPhone through eSIM Carrier Activation or by scanning a QR code from your carrier.
How do I transfer my number to the new phone?
If you upgrade your phone and need a new SIM card, your mobile phone company should transfer your number over on request when you activate your new SIM. This is sometimes referred to as a SIM swap. Take a look on your phone company's website to see its process for doing this or give it a call.