Royal Mail have yet to implement any integration with Opencart... So this module follows the only work-around available at this time which is via DropBox.
Don't worry, once setup it will be completely automated but unfortunately requires a DropBox account and some setup in order to work. Which you can follow our guide or pay us a small fee to do this for you, see below.
Let Us Set You Up
We can help you setup your Royal Mail Click & Drop for you if you are struggling, don't have time or are unfamiliar with all the required fiddling, we only charge £60 for this service, but we will need access to your dropbox, admin panel of opencart and your Royal Mail Click & Drop Account.
Buy Our Install & Setup Service
Set It Up Yourself
Please follow the instructions carefully that are included in the ZIP and available on the Documentation.
Thanks to https://www.opencart.com/index.php?route=marketplace/extension/info&extension_id=33426 where this mod was converted from.