PDF Viewer uses Apple Files App Interface to show files and folders, both local files, iCloud and 3rd-party Cloud Storage Providers such as Dropbox, OneDrive, Google Drive or Box. (Since PDF Viewer 2.1 and iOS 11 or newer)
If you experience issues with file syncing, problems with downloading or uploading files, please reach out to your Cloud Storage Provider and ask for support.
PDF Viewer can only change the color and add icons to the existing Apple Files interface - we do not have control over other details, and unfortunately are unable to help with specific file transfer issues.
Google Drive: https://productforums.google.com/forum/#!forum/drive
You can temporarily copy the files into the local storage of PDF Viewer or iCloud while you are working on them, and then export them back into the preferred cloud storage when you finish editing, like so:
- In the Document Browser view, long-press on the document
- A menu bar will appear, tap on "Move" in the menu bar
- Now select either "On My iPad/iPhone" or "iCloud Drive" and choose your destination
- Tap on "Move" to move the document to the new destination.