At checkout, choose Delivery or Collection (self pickup from the seller). For Delivery, you'll also pick your delivery district. Some sellers set a flat delivery price for buyers in the same district as their listing — if your district matches, that price is added automatically and you pay it upfront with the item, no surprises.
If your district is different from the listing's, the item payment goes through on its own and the order shows "Delivery quote pending." The seller then sends you a price for delivering to your specific address — open the order to accept and pay it (a separate payment, confirmed the same way as your original one) or decline it. Declining automatically switches the order to self pickup instead, no need to cancel and reorder.