Hey there @SILVACITYS!
Welcome to the community :),
Changing your SIM card is not a requirement when upgrade to a new device, unless the old SIM is not compatible with the new phone. The SIM card comes in Regular, Micro and Nano formats, which we usually provide with your new phone order.
Currently I'm assuming you went ahead and upgraded to a new device since you said "upgrade". If the change applied to your account is only a plan change to add data, then you do no not need a new SIM card. You can simply keep using your services as usual since no equipment changes have been made.
Hope this clarifies, and let us know if you have any questions.