One of the issues that couriers have when it comes to delivering parcels is the accuracy of addresses. We do help during the booking process as for deliveries in the UK we offer a Post Code look-up service where you can submit the postcode and click "Find Address". Our database will then provide a list of all the full addresses related to that postcode - both residential and commercial.
If you don't know the postcode but do know part of the address then you can use the Royal Mail address finder to find a list a range of possible options. Do note, however, that for a particular house number it may show a range of sub-addresses such as flat numbers.
We do not have address look-up facilities for international locations. Many local postal services do offer them such as USPS for the USA while there are services which cover Europe such as France Code Postal, you could use Google maps to find an address and postcode. Only search using as much information as you have, and you should be able to find the full address and postcode.