If you already have your new phone and it uses the same SIM card size as your current one, you can simply transfer your SIM into it.
Set up your SIM card
Make sure the device is turned off
Locate the SIM card slot and insert your SIM (refer to the manufacturer’s guide for help)
Turn on your device and complete the automatic activation (connect to Wi-Fi if you do not have a data plan)
Restart your device