Files will not open in Adobe Reader

I am using Adobe Scan app on Android. The app functions well and saves as a PDF. Whenever I try to open on ANY other app, I get an unknown file error. I do not wish to reopen every single app and convert it to a usable file type to use on my Adobe reader, so how can I correct this severe programming error within the app, or is there a quick work-around before I leave a review? Thanks!