If you want to upload file from or to DropBox through Raspberry Pi, it is easy to do so. The following will show you a a installation program and its setup steps.
Step 1. Setup DropBox account and apps from web
First of all you need a DropBox account and apps account through the following links. Hop on over to dropbox is free.
You then need to visit this link https://www.dropbox.com/developers/apps, login to DropBox and create an “app” by clicking the “create app” button.
Then choose “Dropbox API app”, “Files and Datastores”, and answer the final question “Can your app be limited to its own, private folder?” – either answer is OK, depending on your needs. The result will be as below: