Return my new purchased iPhone

Hi,

I just purchased the new iPhone 13 and wanted to return it once it has arrived. I need to change the capacity to a bigger one.

However, I'm just confuse on the procedure.

1) Where can I find the return label (as I need to print this)?

2) How do I proceed with the courier? As I shouldn't be charge on this return process.

Kindly please help me on this. I'm getting nervous to purchase another one due to this uncertainty situation. Thank you.

OthmanNona