In your customer account, select the desired delivery pass duration under "Delivery subscription."
Complete the order process (the delivery pass cannot be purchased at the same time as a food order - it must be purchased separately).
You'll receive immediate e-mail confirmation of your purchase. The delivery pass you ordered will appear immediately under "Delivery subscription." It is valid and can be used without delay (even if you only pay for it later, e.g. using a paying-in slip).