Depending on your address, the courier service provider will leave it either at a parcel shop or depot. The depot is a building of the courier company, usually located in bigger cities. Parcel shops are collection points for parcels which you can find everywhere, from supermarkets to copy shops. To find the nearest depot or parcel shop, simply check the website of the courier.
Your parcel will remain at the depot or parcel shop for five working days. Be aware that after five working days, the parcel will be returned to the sender. Once the courier company returns the package, it is considered to be delivered and the customer will not be compensated.
It may also depend on the delivery address. For locations that are hard to reach, courier companies may only attempt delivery once. This is the case for example for some islands in Greece. These islands are only reachable by plane which is why logistics service providers will not go there everyday.In this case, you will have to contact your local post office and try to schedule a second delivery date or pick it up at the post office.