Expensify folder in Explorer
In my opinion the easiest way to get expenses in the form of a document (pdf, jpg, etc.) into the correct Report would be to have a folder structure directly in Windows explorer or Mac Finder or Mobile devices very similar to how Dropbox is doing it.
I would have an Expensify folder in the Root directory and my Reports would be the subfolders and I can safe documents directly into that subfolder.
Or linking Expensify into Dropbox and have the Expensify Folder Structure in Dropbox would result in the same functionality.