Q: How to change SIM card to new iphonej

From what device to what device?

An iPhone 5C will have a sim tray you can eject to get to the sim card.  What exactly do you want to know?

you get like a paperclip and undo it then stick it in the hole on the sim area and it should come out and then put your new sim card in. just make sure your phone is unlocked

no but you can create an iCloud backup. but keep your contacts if thats all you want then put in the sim card and go to settings contacts and click import sim contacts

The sim card carries no information other than  your cell service and number.

If you need to transfer data such as contacts, photos, etc...  Then you need to restore the new iPhone from a backup of the old one.

Transfer content from an iPhone, iPad, or iPod touch to a new device - Apple Support

actually, a sim card can carry contacts

or, at least my att one does

jschwing2021 wrote:

 

actually, a sim card can carry contacts

or, at least my att one does

Not in an iPhone.

actually, it does i hav iPhone 5 iOS 8.3 as it states down there so you're wrong

OK.

A sim card can have contacts, but the iPhone does not store contacts onto the sim card since it can't write to it.  It can read contacts written to it by other phones though.

From this support article:

Import contacts from your SIM card - Apple Support

Like most cellular phones, the iPhone uses a SIM card to determine the phone number, carrier, and features that are available for the account. Unlike some phones, the iPhone doesn't store contacts and phone numbers on the SIM card.

In any case, it won't have photos or files or anything else either.

And your iPhone did not write those contacts to that SIM. Maybe something else did, another phone, but not the iPhone.

actually, my iPhone writes contacts imported to it. it does it automatically. btw i may be wrong

no, it did it automatically you are wrong