Post offices and post boxes are easy to locate. The post boxes are a stand-out red colour and usually placed at prominent street corners. All post offices, along with localities, have a specified postal code, which should be added in all communications.
In all letters, parcels, you should be sure to write a full address and also include the sender's address and phone details on the left-hand corner of the parcel/letter to ensure that it is sent back in case of non-delivery to its recipient.