Shipping

I was wondering if there's a way to set a default shipping courier. For example, my supplier automatically fulfills my orders when they ship my orders. When orders ship, they are automatically fulfilled on Squarespace, but contained in the confirmation email, is their foreign tracking service. I would like to link another tracking service as default. one that doesn't change. However, if this isn't possible, is there a way to stop the automatic fulfillment of my orders so I can do that manually and just enter the tracking?

I know I am rambling on a lot, but if I can put another courier in the confirmation emails when orders are fulfilled, can I attach a link to them? because I want to use Yodel, which isn't one of the couriers that Squarespace provides to select on confirmation emails. Can I link to the Yodel website to allow tracking?