Your package will be shipped out with either FedEx or USPS.
Standard Shipping (within 10 biz days): Your order will start with Fed Ex, then will be handed off to USPS (this service is called "Fed Ex SmartPost" - you can read about it here)
Expedited Shipping (2-3 biz days): Your order will be shipped to you with Fed Ex the entire way!
Express Shipping (next biz day): Your order will be shipped to you with Fed Ex the entire way!
You can always use the tracking number in your shipping email to double check.