Automatic Upload is available for Dropbox, Google Drive, OneNote, OneDrive, Evernote or any WebDAV server. Scanner Pro will upload a copy of all files you create in it in the storage of your choice.
Note: It only works for new and updated scans, the ones you had in the app before setting auto-upload have to be synced manually.
To set it up for one of the services open the app settings, and tap Select service
Select one of the storages from the list, log into it if necessary and choose the target folder for upload.
Toggle off Use 3G for Auto Upload to restrict upload to wifi.