How do I set up an old iPhone for my son with a new number?

[ReallyQuiteFazed]

How do I set up an old iPhone for my son with a new number?

I have an old iPhone XR and we are keen to get him trying to go to school on his own. I have got a Giffgaff Sim but I don’t know how to get a new phone number. Will the Sim generate a new phone number if I wipe the phone? So if I do a full reset , switch off and Put in the new Sim, where does the new phone number come from?

First Erase the old phone completely, so that it comes back to that Hola / Hello screen. What network did the phone used to use? As you would have to put a new sim in from the old network for it to work. Giffgaff will work in O2 phones as well as their own.

Is the Sim you have a pay as you go Sim only one? The number will come up at the top of the Contacts page as "my number".

Will the sim not have its own phone number?
If you wanted a new phone number you'd get new sim card

Yes I was hoping that the sim will have its own number.

just wiped the phone

I think I need to create an Apple ID for my son? I hope I will be prompted to do this when I go in The phone set up