Upload PDFs to OneDrive from phone

[MBY]

I've been trying to upload emailed PDFs directly to OneDrive. Using the MS PDF reader app, you can open the attachment and share it. But the only share options are via email and the link created is just garbage. And if you try to upload the file from the OneDrive app, the reader documents don't seem to be anywhere accessible like downloads or documents on phone or SD card. Has anyone found a way?