Fill & Sign chrome extension opens to document cloud

We have the same issue/inquiry.
Recently got the Adobe extension in our CAC authenticated work environment, but a PDF opens with 
"Please wait...   If this message is not eventually replaced by the proper
contents of the document, your PDF viewer may not be able to display this
type of document.   You can upgrade to the latest version of Adobe Reader
for WindowsR, Mac, or LinuxR by visiting
http://www.adobe.com/go/reader_download.   For more assistance with Adobe
Reader visit  http://www.adobe.com/go/acrreader.   Windows is either a
registered trademark or a trademark of Microsoft Corporation in the United
States and/or other countries. Mac is a trademark of Apple Inc., registered
in the United States and other countries. Linux is the registered trademark
of Linus Torvalds in the U.S. and other countries."

And has "Sign in to download" at the top right.

Issue: We want to be able to sign PDFs saved in SharePoint 2016 in the browser and save, but we cannot.
This new extension seems like a step in the right direction- except it doesn't go anywhere.